Organometallic compound and organic light-emitting device including the same

ABSTRACT

An organometallic compound represented by Formula 1:
 
M(L 1 ) n1 (L 2 ) n2   Formula 1
 
wherein, in Formula 1,
     L 1  is a ligand represented by Formula 2,   L 2  is a ligand represented by one of Formulae 3 to 5, and   n1 and n2 are each independently 1 or 2,
 
wherein Formulae 1 to 5 are described in the specification.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of Korean Patent Application No.10-2014-0027947, filed on Mar. 10, 2014, in the Korean IntellectualProperty Office, and all the benefits accruing therefrom under 35 U.S.C.§ 119, the disclosure of which is incorporated herein in its entirety byreference.

BACKGROUND

1. Field

The present inventive concept relates to organometallic compounds andorganic light-emitting devices including the organometallic compounds

2. Description of the Related Art

Organic light-emitting devices (OLEDs) are self-emitting devices, whichhave advantages such as wide viewing angles, excellent contrast ratios,and quick response times. In addition, the OLEDs exhibit highbrightness, excellent driving voltage characteristics, and can providemulticolored images.

A typical organic light-emitting device may include an anode, a cathode,and an organic layer, including an emission layer, disposed between theanode and the cathode. The organic light-emitting device may alsoinclude a hole transport region disposed between the anode and theemission layer, and an electron transport region disposed between theemission layer and the cathode. Holes injected from the anode move tothe emission layer via the hole transport region, while electronsinjected from the cathode move to the emission layer via the electrontransport region. Carriers such as the holes and electrons recombine inan emission layer to generate excitons. When the excitons drop from anexcited state to a ground state, light is emitted.

Various types of organic light emitting devices are known. However,there still remains a need in OLEDs having low driving voltage, highefficiency, high brightness, and long lifespan.

SUMMARY

Provided are organometallic compounds and organic light-emitting devicesincluding the organometallic compounds.

Additional aspects will be set forth in part in the description whichfollows and, in part, will be apparent from the description, or may belearned by practice of the presented embodiments.

According to an aspect of the present inventive concept, anorganometallic compound represented by Formula 1 is provided:M(L₁)_(n1)(L₂)_(n2)  Formula 1

wherein, in Formula 1,

L₁ is a ligand represented by Formula 2, and

L₂ is a ligand represented by one of Formulae 3 to 5:

wherein, in Formulae 1 to 5,

M is Ir, Pt, Os, Ti, Zr, Hf, Eu, Th, or Tm;

CY₁ and CY₂ are each independently a benzene, a naphthalene, a fluorene,a spiro-fluorene, an indene, a pyrrole, a thiophene, a furan, animidazole, a pyrazole, a thiazole, an isothiazole, an oxazole, anisoxazole, a pyridine, a pyrazine, a pyrimidine, a pyridazine, aquinoline, an isoquinoline, a benzoquinoline, a quinoxaline, aquinazoline, a carbazole, a benzoimidazole, a benzofuran, abenzothiophene, an isobenzothiophene, an benzoxazole, an isobenzoxazole,a triazole, a tetrazole, an oxadiazole, a triazine, a dibenzofuran, or adibenzothiophene, wherein CY₁ and CY₂ are optionally linked to eachother via a single bond or a first linking group;

Y₁ to Y₄ are each independently C or N;

Y₁ and Y₂ are linked to each other via a single bond or a double bond,and

Y₃ and Y₄ are linked to each other via a single bond or a double bond;

X₁ is N or CR₁;

X₂ is N or CR₂;

X₃ is N or CR₃;

X₄ is N or CR₄;

X₁₁ is N or CR₁₁;

X₁₂ is N or CR₁₂;

X₁₃ is N or CR₁₃;

X₁₄ is N or CR₁₄;

X₁₅ is N or CR₁₅;

X₁₆ is N or CR₁₆;

Z₁ to Z₄, R₁ to R₄, R₁₁ to R₁₆, R₂₁, R₂₂, and Q₅₁ to Q₅₉ are eachindependently a hydrogen, a deuterium, —F, —Cl, —Br, —I, a hydroxylgroup, a cyano group, a nitro group, an amino group, an amidino group, ahydrazine group, a hydrazone group, a carboxylic acid group or a saltthereof, a sulfonic acid group or a salt thereof, a phosphoric acidgroup or a salt thereof, a substituted or unsubstituted C₁-C₆₀ alkylgroup, a substituted or unsubstituted C₂-C₆₀ alkenyl group, asubstituted or unsubstituted C₂-C₆₀ alkynyl group, a substituted orunsubstituted C₁-C₆₀ alkoxy group, a substituted or unsubstituted C₃-C₁₀cycloalkyl group, a substituted or unsubstituted C₂-C₁₀ heterocycloalkylgroup, a substituted or unsubstituted C₃-C₁₀ cycloalkenyl group, asubstituted or unsubstituted C₂-C₁₀ heterocycloalkenyl group, asubstituted or unsubstituted C₆-C₆₀ aryl group, a substituted orunsubstituted C₆-C₆₀ aryloxy group, a substituted or unsubstitutedC₆-C₆₀ arylthio group, a substituted or unsubstituted C₂-C₆₀ heteroarylgroup, a substituted or unsubstituted monovalent non-aromatic condensedpolycyclic group, a substituted or unsubstituted monovalent non-aromaticcondensed heteropolycyclic group, or —Si(Q₁)(Q₂)(Q₃), wherein R₂₁ andR₂₂ are optionally linked to each other via a single bond or a secondlinking group represented by Formula 7:*—(Z₃₂)_(b2)—*′  Formula 7

Z₃₂ is *—O—*′, *—S—*′, *—N(Q₅₁)—*′, *—C(Q₅₂)(Q₅₃)—*′,*—C(Q₅₄)═C(Q₅₅)—*′, or

b2 is an integer selected from 1 to 10, and when b2 is 2 or greater,groups Z₃₂ are identical to or different from each other;

a1 and a2 are each independently an integer selected from 0 to 5;

n1 and n2 are each independently 1 or 2;

* and *′ each indicates a binding site to M in Formula 1;

when the ligand of Formula 2 is represented by Formula 2A, a2 in Formula2A is 2, and Z₂ in Formula 2A is —F;

at least one of X₁₁ to X₁₆ in Formula 4 is N;

the following conditions regarding R₂₁ and R₂₂ in Formula 5 are excluded

i) where R₂₁ and R₂₂ are both phenyl groups,

ii) where R₂₁ and R₂₂ are both phenyl groups substituted with atert-butyl group,

iii) where R₂₁ and R₂₂ are both ethyl groups,

iv) where R₂₁ and R₂₂ are both propyl groups,

v) where R₂₁ and R₂₂ are both butyl groups, and

vi) where R₂₁ and R₂₂ are both —Si(CH₃)₃;

at least one substituent of the substituted C₁-C₆₀ alkyl group, thesubstituted C₂-C₆₀ alkenyl group, the substituted C₂-C₆₀ alkynyl group,the substituted C₁-C₆₀ alkoxy group, the substituted C₃-C₁₀ cycloalkylgroup, the substituted C₂-C₁₀ heterocycloalkyl group, the substitutedC₃-C₁₀ cycloalkenyl group, the substituted C₂-C₁₀ heterocycloalkenylgroup, the substituted C₆-C₆₀ aryl group, the substituted C₆-C₆₀ aryloxygroup, the substituted C₆-C₆₀ arylthio group, the substituted C₂-C₆₀heteroaryl group, the substituted monovalent non-aromatic condensedpolycyclic group, and the substituted monovalent non-aromatic condensedheteropolycyclic group is

a deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitrogroup, an amino group, an amidino group, a hydrazine group, a hydrazonegroup, a carboxylic acid group or a salt thereof, a sulfonic acid groupor a salt thereof, a phosphoric acid group or a salt thereof, a C₁-C₆₀alkyl group, a C₂-C₆₀ alkenyl group, a C₂-C₆₀ alkynyl group, or a C₁-C₆₀alkoxy group,

a C₁-C₆₀ alkyl group, a C₂-C₆₀ alkenyl group, a C₂-C₆₀ alkynyl group, ora C₁-C₆₀ alkoxy group, each substituted with at least one of adeuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitrogroup, an amino group, an amidino group, a hydrazine group, a hydrazonegroup, a carboxylic acid group or a salt thereof, a sulfonic acid groupor a salt thereof, a phosphoric acid group or a salt thereof, a C₃-C₁₀cycloalkyl group, a C₂-C₁₀ heterocycloalkyl group, a C₃-C₁₀ cycloalkenylgroup, a C₂-C₁₀ heterocycloalkenyl group, a C₆-C₆₀ aryl group, a C₆-C₆₀aryloxy group, a C₆-C₆₀ arylthio group, a C₂-C₁₀ heteroaryl group, amonovalent non-aromatic condensed polycyclic group, a monovalentnon-aromatic condensed heteropolycyclic group, —N(Q₁₁)(Q₁₂),—Si(Q₁₃)(Q₁₄)(Q₁₅), and —B(Q₁₆)(Q₁₇),

a C₃-C₁₀ cycloalkyl group, a C₂-C₁₀ heterocycloalkyl group, a C₃-C₁₀cycloalkenyl group, a C₂-C₁₀ heterocycloalkenyl group, a C₆-C₆₀ arylgroup, a C₆-C₆₀ aryloxy group, a C₆-C₆₀ arylthio group, a C₂-C₆₀heteroaryl group, a monovalent non-aromatic condensed polycyclic group,or a monovalent non-aromatic condensed heteropolycyclic group,

a C₃-C₁₀ cycloalkyl group, a C₂-C₁₀ heterocycloalkyl group, a C₃-C₁₀cycloalkenyl group, a C₂-C₁₀ heterocycloalkenyl group, a C₆-C₆₀ arylgroup, a C₆-C₆₀ aryloxy group, a C₆-C₆₀ arylthio group, a C₂-C₆₀heteroaryl group, a monovalent non-aromatic condensed polycyclic group,or a monovalent non-aromatic condensed heteropolycyclic group, eachsubstituted with at least one of a deuterium, —F, —Cl, —Br, —I, ahydroxyl group, a cyano group, a nitro group, an amino group, an amidinogroup, a hydrazine group, a hydrazone group, a carboxylic acid group ora salt thereof, a sulfonic acid group or a salt thereof, a phosphoricacid group or a salt thereof, a C₁-C₆₀ alkyl group, a C₂-C₆₀ alkenylgroup, a C₂-C₆₀ alkynyl group, a C₁-C₆₀ alkoxy group, a C₃-C₁₀cycloalkyl group, a C₂-C₁₀ heterocycloalkyl group, a C₃-C₁₀ cycloalkenylgroup, a C₂-C₁₀ heterocycloalkenyl group, a C₆-C₆₀ aryl group, a C₆-C₆₀aryloxy group, a C₆-C₆₀ arylthio group, a C₂-C₆₀ heteroaryl group, amonovalent non-aromatic condensed polycyclic group, a monovalentnon-aromatic condensed heteropolycyclic group, —N(Q₂₁)(Q₂₂),—Si(Q₂₃)(Q₂₄)(Q₂₅), and —B(Q₂₆)(Q₂₇), or

—N(Q₃₁)(Q₃₂), —Si(Q₃₃)(Q₃₄)(Q₃₅), or —B(Q₃₆)(Q₃₇); wherein

Q₁ to Q₃, Q₁₁ to Q₁₇, Q₂₁ to Q₂₇, and Q₃₁ to Q₃₇ are each independentlya hydrogen, a deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyanogroup, a nitro group, an amino group, an amidino group, a hydrazinegroup, a hydrazone group, a carboxylic acid group or a salt thereof, asulfonic acid group or a salt thereof, a phosphoric acid group or a saltthereof, a C₁-C₆₀ alkyl group, a C₂-C₆₀ alkenyl group, a C₂-C₆₀ alkynylgroup, a C₁-C₆₀ alkoxy group, a C₃-C₁₀ cycloalkyl group, a C₂-C₁₀heterocycloalkyl group, a C₃-C₁₀ cycloalkenyl group, a C₂-C₁₀heterocycloalkenyl group, a C₆-C₆₀ aryl group, a C₆-C₆₀ aryloxy group, aC₆-C₆₀ arylthio group, a C₂-C₆₀ heteroaryl group, a monovalentnon-aromatic condensed polycyclic group, or a monovalent non-aromaticcondensed heteropolycyclic group:

According to another aspect of the present inventive concept, an organiclight-emitting device comprising: a first electrode; a second electrode;and an organic layer disposed between the first electrode and the secondelectrode and comprising an emission layer and at least one of theorganometallic compounds.

BRIEF DESCRIPTION OF THE DRAWINGS

These and/or other aspects will become apparent and more readilyappreciated from the following description of the embodiments, taken inconjunction with the accompanying drawings of which:

FIG. 1 is a schematic cross-sectional view of an organic light-emittingdevice according to an embodiment of the present disclosure; and

FIGS. 2 to 14 are graphs of emission intensity (arbitrary unit, a. u.)versus wavelength (nanometer, nm) illustrating photoluminescent (PL)spectra of Compounds 52, 19, 2, 50, 1, 3, 5, 9, 54, 53, 51, 56, and 30,respectively.

DETAILED DESCRIPTION

Reference will now be made in detail to embodiments, examples of whichare illustrated in the accompanying drawings, wherein like referencenumerals refer to the like elements throughout. In this regard, thepresent embodiments may have different forms and should not be construedas being limited to the descriptions set forth herein. Accordingly, theembodiments are merely described below, by referring to the figures, toexplain aspects of the present description. As used herein, the term“and/or” includes any and all combinations of one or more of theassociated listed items. Expressions such as “at least one of,” whenpreceding a list of elements, modify the entire list of elements and donot modify the individual elements of the list.

It will be understood that when an element is referred to as being “on”another element, it can be directly in contact with the other element orintervening elements may be present therebetween. In contrast, when anelement is referred to as being “directly on” another element, there areno intervening elements present.

It will be understood that, although the terms first, second, third etc.may be used herein to describe various elements, components, regions,layers, and/or sections, these elements, components, regions, layers,and/or sections should not be limited by these terms. These terms areonly used to distinguish one element, component, region, layer, orsection from another element, component, region, layer, or section.Thus, a first element, component, region, layer, or section discussedbelow could be termed a second element, component, region, layer, orsection without departing from the teachings of the present embodiments.

The terminology used herein is for the purpose of describing particularembodiments only and is not intended to be limiting. As used herein, thesingular forms “a,” “an,” and “the” are intended to include the pluralforms as well, unless the context clearly indicates otherwise.

The term “or” means “and/or.” It will be further understood that theterms “comprises” and/or “comprising,” or “includes” and/or “including”when used in this specification, specify the presence of statedfeatures, regions, integers, steps, operations, elements, and/orcomponents, but do not preclude the presence or addition of one or moreother features, regions, integers, steps, operations, elements,components, and/or groups thereof.

Unless otherwise defined, all terms (including technical and scientificterms) used herein have the same meaning as commonly understood by oneof ordinary skill in the art to which this general inventive conceptbelongs. It will be further understood that terms, such as those definedin commonly used dictionaries, should be interpreted as having a meaningthat is consistent with their meaning in the context of the relevant artand the present disclosure, and will not be interpreted in an idealizedor overly formal sense unless expressly so defined herein.

Exemplary embodiments are described herein with reference to crosssection illustrations that are schematic illustrations of idealizedembodiments. As such, variations from the shapes of the illustrations asa result, for example, of manufacturing techniques and/or tolerances,are to be expected. Thus, embodiments described herein should not beconstrued as limited to the particular shapes of regions as illustratedherein but are to include deviations in shapes that result, for example,from manufacturing. For example, a region illustrated or described asflat may, typically, have rough and/or nonlinear features. Moreover,sharp angles that are illustrated may be rounded. Thus, the regionsillustrated in the figures are schematic in nature and their shapes arenot intended to illustrate the precise shape of a region and are notintended to limit the scope of the present claims.

According to an embodiment of the present inventive concept, there isprovided an organometallic compound represented by Formula 1:M(L₁)_(n1)(L₂)_(n2)  Formula 1

In Formula 1, L₁ may be a ligand represented by Formula 2, and L₂ may bea ligand represented by one of Formulae 3 to 5:

In Formulae 2 to 5, * and *′ each indicates a binding site to M inFormula 1. Thus, the organometallic compound of Formula 1 may berepresented by Formula 1A, 1B, or 1C:

In Formulae 1A to 1C, M, CY₁, CY₂, Y₁ to Y₄, X₁ to X₄, X₁₁ to X₁₆, Z₁ toZ₄, R₂₁, R₂₂, n1, and n2 are the same as those defined herein.

In Formula 1, M may be iridium (Ir), platinum (Pt), osmium (Os),titanium (Ti), zirconium (Zr), hafnium (Hf), europium (Eu), terbium(Tb), or thulium (Tm). For example, M in Formula 1 may be Ir or Pt.

In Formula 2, CY₁ and CY₂ may be each independently a benzene, anaphthalene, a fluorene, a spiro-fluorene, an indene, a pyrrole, athiophene, a furan, an imidazole, a pyrazole, a thiazole, anisothiazole, an oxazole, an isoxazole, a pyridine, a pyrazine, apyrimidine, a pyridazine, a quinoline, an isoquinoline, abenzoquinoline, a quinoxaline, a quinazoline, a carbazole, abenzoimidazole, a benzofuran, a benzothiophene, an isobenzothiophene, abenzoxazole, an isobenzoxazole, a triazole, a tetrazole, an oxadiazole,a triazine, a dibenzofuran, or a dibenzothiophene, wherein CY₁ and CY₂may be optionally linked to each other via a single bond or a firstlinking group.

The first linking group may be represented by Formula 6:*—(Z₃₁)_(b1)—*′  Formula 6

In Formula 6, Z₃₁ may be *—O—*′, *—S—*′, *—N(Q₄₁)—*′, *—C(Q₄₂)(Q₄₃)—*′,*—C(Q₄₄)═C(Q₄₅)—*′, or

wherein Q₄₁ to Q₄₉ may be each independently

a hydrogen, a deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyanogroup, a nitro group, an amino group, an amidino group, a hydrazinegroup, a hydrazone group, a carboxylic acid group or a salt thereof, asulfonic acid group or a salt thereof, a phosphoric acid group or a saltthereof, a C₁-C₆₀ alkyl group, a C₂-C₆₀ alkenyl group, a C₂-C₆₀ alkynylgroup, or a C₁-C₆₀ alkoxy group,

a C₁-C₆₀ alkyl group, a C₂-C₆₀ alkenyl group, a C₂-C₆₀ alkynyl group, ora C₁-C₆₀ alkoxy group, each substituted with at least one of adeuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitrogroup, an amino group, an amidino group, a hydrazine group, a hydrazonegroup, a carboxylic acid group or a salt thereof, a sulfonic acid groupor a salt thereof, a phosphoric acid group or a salt thereof, a C₃-C₁₀cycloalkyl group, a C₂-C₁₀ heterocycloalkyl group, a C₃-C₁₀ cycloalkenylgroup, a C₂-C₁₀ heterocycloalkenyl group, a C₆-C₆₀ aryl group, a C₆-C₆₀aryloxy group, a C₆-C₆₀ arylthio group, a C₂-C₆₀ heteroaryl group, amonovalent non-aromatic condensed polycyclic group, and a monovalentnon-aromatic condensed heteropolycyclic group,

a C₃-C₁₀ cycloalkyl group, a C₂-C₁₀ heterocycloalkyl group, a C₃-C₁₀cycloalkenyl group, a C₂-C₁₀ heterocycloalkenyl group, a C₆-C₆₀ arylgroup, a C₆-C₆₀ aryloxy group, a C₆-C₆₀ arylthio group, a C₂-C₆₀heteroaryl group, a monovalent non-aromatic condensed polycyclic group,or a monovalent non-aromatic condensed heteropolycyclic group, or

a C₃-C₁₀ cycloalkyl group, a C₂-C₁₀ heterocycloalkyl group, a C₃-C₁₀cycloalkenyl group, a C₂-C₁₀ heterocycloalkenyl group, a C₆-C₆₀ arylgroup, a C₆-C₆₀ aryloxy group, a C₆-C₆₀ arylthio group, a C₂-C₆₀heteroaryl group, a monovalent non-aromatic condensed polycyclic group,or a monovalent non-aromatic condensed heteropolycyclic group, eachsubstituted with at least one of a deuterium, —F, —Cl, —Br, —I, ahydroxyl group, a cyano group, a nitro group, an amino group, an amidinogroup, a hydrazine group, a hydrazone group, a carboxylic acid group ora salt thereof, a sulfonic acid group or a salt thereof, a phosphoricacid group or a salt thereof, a C₁-C₆₀ alkyl group, a C₂-C₆₀ alkenylgroup, a C₂-C₆₀ alkynyl group, a C₁-C₆₀ alkoxy group, a C₃-C₁₀cycloalkyl group, a C₂-C₁₀ heterocycloalkyl group, a C₃-C₁₀ cycloalkenylgroup, a C₂-C₁₀ heterocycloalkenyl group, a C₆-C₆₀ aryl group, a C₆-C₆₀aryloxy group, a C₆-C₆₀ arylthio group, a C₂-C₆₀ heteroaryl group, amonovalent non-aromatic condensed polycyclic group, and a monovalentnon-aromatic condensed heteropolycyclic group; and

b1 in Formula 6 may be an integer selected from 1 to 10, and when b1 is2 or greater, groups Z₃₁ may be identical to or different from eachother.

For example, in Formula 6, Q₄₁ to Q₄₉ may be each independently

a hydrogen, a deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyanogroup, a nitro group, an amino group, an amidino group, a hydrazinegroup, a hydrazone group, a carboxylic acid group or a salt thereof, asulfonic acid group or a salt thereof, a phosphoric acid group or a saltthereof, a C₁-C₂₀ alkyl group, or a C₁-C₂₀ alkoxy group,

a C₁-C₂₀ alkyl group or a C₁-C₂₀ alkoxy group, each substituted with atleast one of a deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyanogroup, a nitro group, an amino group, an amidino group, a hydrazinegroup, a hydrazone group, a carboxylic acid group or a salt thereof, asulfonic acid group or a salt thereof, a phosphoric acid group or a saltthereof, a phenyl group, a naphthyl group, a pyridinyl group, and apyrimidinyl group, or

a phenyl group, a naphthyl group, a pyridinyl group, or a pyrimidinylgroup. However, embodiments of the present inventive concept are notlimited thereto.

For example, in Formula 2, CY₁ and CY₂ may be linked to each other via asingle bond or a first linking group, and the first linking group may berepresented by *—C(Q₄₄)═C(Q₄₅)—*′ or

(where b1 in Formula 6 is 1), wherein Q₄₄ to Q₄₉ may be eachindependently a hydrogen, a C₁-C₁₀ alkyl group, or a C₁-C₁₀ alkoxygroup. However, embodiments of the present inventive concept are notlimited thereto.

In some embodiments, in Formula 2, CY₁ and CY₂ may be each independentlya benzene, a naphthalene, a fluorene, a thiophene, a furan, animidazole, a pyrazole, a pyridine, a pyrimidine, a quinoline, anisoquinoline, a benzoquinoline, a quinoxaline, a quinazoline, acarbazole, a benzoimidazole, a benzofuran, a benzothiophene, anisobenzothiophene, a triazole, a tetrazole, a triazine, a dibenzofuran,or a dibenzothiophene.

In some embodiments, CY₁ may be a pyridine or an imidazole, and CY₂ maybe a benzene, a pyridine, or a dibenzofuran.

In Formula 2, Y₁ to Y₄ may be each independently a carbon (C) or anitrogen (N). In Formula 2, Y₁ and Y₂ may be linked to each other via asingle bond or a double bond, and Y₃ and Y₄ may be linked to each othervia a single bond or a double bond.

For example, in Formula 2, Y₁ may be N, and Y₂ to Y₄ may be C. In someother embodiments, in Formula 2, Y₁, Y₃, and Y₄ may be C, and Y₂ may beN.

In some embodiments, when the ligand of Formula 2 is represented byFormula 2A, a2 in Formula 2A is 2, and Z₂ is —F:

In some embodiments, L₁ in Formula 1 may be selected from groupsrepresented by Formulae 2-1 to 2-90:

In Formulae 2-1 to 2-90,

Z₁ and Z₂ may be the same as those defined above;

Z_(1a) and Z_(1b) are the same or different and may each have the samedefinition as Z₁;

Z_(2a), Z_(2b) and Z_(2c) are the same or different and may each havethe same definition as Z₂;

a12 may be 1 or 2;

a13 may be an integer selected from 1 to 3;

a14 may be an integer selected from 1 to 4; and

* and *′ each indicates a binding site to M.

For example, in Formulae 2-1 to 2-90, Z₁, Z₂, Z_(1a), Z_(1b), Z_(2a),Z_(2b), and Z_(2c) may be each independently

a hydrogen, —F, a cyano group, a nitro group, a methyl group, an ethylgroup, n-propyl group, an isopropyl group, n-butyl group, an isobutylgroup, a sec-butyl group, a tert-butyl group, a n-pentyl group, anisopentyl group, a sec-pentyl group, a tert-pentyl group, a n-hexylgroup, an isohexyl group, a sec-hexyl group, a tert-hexyl group, an-heptyl group, an isoheptyl group, a sec-heptyl group, a tert-heptylgroup, a n-octyl group, an isooctyl group, a sec-octyl group, atert-octyl group, a n-nonyl group, an isononyl group, a sec-nonyl group,a tert-nonyl group, a n-decyl group, an isodecyl group, a sec-decylgroup, a tert-decyl group, a methoxy group, an ethoxy group, a propoxygroup, a butoxy group, a pentoxy group, a phenyl group, or a naphthylgroup, or

a methyl group, an ethyl group, a n-propyl group, an isopropyl group,n-butyl group, an isobutyl group, a sec-butyl group, a tert-butyl group,a n-pentyl group, an isopentyl group, a sec-pentyl group, a tert-pentylgroup, a n-hexyl group, an isohexyl group, a sec-hexyl group, atert-hexyl group, a n-heptyl group, an isoheptyl group, a sec-heptylgroup, a tert-heptyl group, a n-octyl group, an isooctyl group, asec-octyl group, a tert-octyl group, a n-nonyl group, an isononyl group,a sec-nonyl group, a tert-nonyl group, a n-decyl group, an isodecylgroup, a sec-decyl group, a tert-decyl group, a methoxy group, an ethoxygroup, a propoxy group, a butoxy group, a pentoxy group, a phenyl group,or a naphthyl group, each substituted with at least one of —F, a cyanogroup, and a nitro group. However, embodiments of the present inventiveconcept are not limited thereto.

In some other embodiments, L₁ in Formula 1 may be selected from groupsrepresented by Formulae 2-1A, 2-2a, 2-70A, and 2-87A:

In Formulae 2-1A, 2-2A, 2-70A, and 2-87A,

Z₁ and Z₂ may be the same as those defined above,

Z_(2a), Z_(2b), and Z_(2c) are the same or different and may each havethe same definition as Z₂, and

* and *′ each indicates a binding site to M.

In Formulae 4 and 5,

X₁ may be N or CR₁;

X₂ may be N or CR₂;

X₃ may be N or CR₃;

X₄ may be N or CR₄;

X₁₁ may be N or CR₁₁;

X₁₂ may be N or CR₁₂;

X₁₃ may be N or CR₁₃;

X₁₄ may be N or CR₁₄;

X₁₅ may be N or CR₁₅;

X₁₆ may be N or CR₁₆; and

at least one of X₁₁ to X₁₆ in Formula 5 may be N.

In some embodiments, at least one of X₁ to X₄ in Formula 3 may be N.

In some embodiments, Z₁ to Z₄, R₁ to R₄, R₁₁ to R₁₆, R₂₁, R₂₂, and Q₅₁to Q₅₉ in above Formulae may be each independently a hydrogen, adeuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitrogroup, an amino group, an amidino group, a hydrazine group, a hydrazonegroup, a carboxylic acid group or a salt thereof, a sulfonic acid groupor a salt thereof, a phosphoric acid group or a salt thereof, asubstituted or unsubstituted C₁-C₆₀ alkyl group, a substituted orunsubstituted C₂-C₆₀ alkenyl group, a substituted or unsubstitutedC₂-C₆₀ alkynyl group, a substituted or unsubstituted C₁-C₆₀ alkoxygroup, a substituted or unsubstituted C₃-C₁₀ cycloalkyl group, asubstituted or unsubstituted C₂-C₁₀ heterocycloalkyl group, asubstituted or unsubstituted C₃-C₁₀ cycloalkenyl group, a substituted orunsubstituted C₂-C₁₀ heterocycloalkenyl group, a substituted orunsubstituted C₆-C₆₀ aryl group, a substituted or unsubstituted C₆-C₆₀aryloxy group, a substituted or unsubstituted C₆-C₆₀ arylthio group, asubstituted or unsubstituted C₂-C₆₀ heteroaryl group, a substituted orunsubstituted monovalent non-aromatic condensed polycyclic group, asubstituted or unsubstituted monovalent non-aromatic condensedheteropolycyclic group, or —Si(Q₁)(Q₂)(Q₃); and

R₂₁ and R₂₂ may be optionally linked to each other via a single bond ora second linking group represented by Formula 7:*—(Z₃₂)_(b2)—*′  Formula 7

In Formula 7, Z₃₂ is *—O—*′, *—S—*′, *—N(Q₅₁)—*′, *—C(Q₅₂)(Q₅₃)—*′,—C(Q₅₄)═C(Q₅₅)—*′, or

b2 is an integer selected from 1 to 10, and when b2 is 2 or greater,groups Z₃₂ are identical to or different from each other;

In Formula 5, the following conditions regarding R₂₁ and R₂₂ areexcluded:

i) where R₂₁ and R₂₂ are both phenyl groups,

ii) where R₂₁ and R₂₂ are both phenyl groups substituted with atert-butyl group,

iii) where R₂₁ and R₂₂ are both ethyl groups,

iv) where R₂₁ and R₂₂ are both propyl groups,

v) where R₂₁ and R₂₂ are both butyl groups, and

vi) where R₂₁ and R₂₂ are both —Si(CH₃)₃.

In some other embodiments, Z₁ to Z₄, R₁ to R₄, R₁₁ to R₁₆, R₂₁, R₂₂, andQ₅₁ to Q₅₉ in above Formulae may be each independently

a hydrogen, a deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyanogroup, a nitro group, an amino group, an amidino group, a hydrazinegroup, a hydrazone group, a carboxylic acid group or a salt thereof, asulfonic acid group or a salt thereof, a phosphoric acid group or a saltthereof, a C₁-C₂₀ alkyl group, or a C₁-C₂₀ alkoxy group,

a C₁-C₂₀ alkyl group or a C₁-C₂₀ alkoxy group, each substituted with atleast one of a deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyanogroup, a nitro group, an amino group, an amidino group, a hydrazinegroup, a hydrazone group, a carboxylic acid group or a salt thereof, asulfonic acid group or a salt thereof, a phosphoric acid group or a saltthereof, a phenyl group, a naphthyl group, a pyridinyl group, and apyrimidinyl group,

a phenyl group, a pentalenyl group, an indenyl group, a naphthyl group,an azulenyl group, a heptalenyl group, an indacenyl group, anacenaphthyl group, a fluorenyl group, a spiro-fluorenyl group, abenzofluorenyl group, a dibenzofluorenyl group, a phenalenyl group, aphenanthrenyl group, an anthracenyl group, a fluoranthenyl group, atriphenylenyl group, a pyrenyl group, a chrysenyl group, a naphthacenylgroup, a picenyl group, a perylenyl group, a pentaphenyl group, ahexacenyl group, a pentacenyl group, a rubicenyl group, a coronenylgroup, a ovalenyl group, a pyrrolyl group, a thiophenyl group, a furanylgroup, an imidazolyl group, a pyrazolyl group, a thiazolyl group, anisothiazolyl group, a oxazolyl group, an isooxazolyl group, a pyridinylgroup, a pyrazinyl group, a pyrimidinyl group, a pyridazinyl group, anisoindolyl group, an indolyl group, an indazolyl group, a purinyl group,a quinolinyl group, an isoquinolinyl group, a benzoquinolinyl group, aphthalazinyl group, a naphthyridinyl group, a quinoxalinyl group, aquinazolinyl group, a cinnolinyl group, a carbazolyl group, aphenanthridinyl group, an acridinyl group, a phenanthrolinyl group, aphenazinyl group, a benzoimidazolyl group, a benzofuranyl group, abenzothiophenyl group, an isobenzothiazolyl group, a benzooxazolylgroup, an isobenzooxazolyl group, a triazolyl group, a tetrazolyl group,a oxadiazolyl group, a triazinyl group, a dibenzofuranyl group, adibenzothiophenyl group, a benzocarbazolyl group, a dibenzocarbazolylgroup, a thiadiazolyl group, an imidazopyridinyl group, or animidazopyrimidinyl group,

a phenyl group, a pentalenyl group, an indenyl group, a naphthyl group,an azulenyl group, a heptalenyl group, an indacenyl group, anacenaphthyl group, a fluorenyl group, a spiro-fluorenyl group, abenzofluorenyl group, a dibenzofluorenyl group, a phenalenyl group, aphenanthrenyl group, an anthracenyl group, a fluoranthenyl group, atriphenylenyl group, a pyrenyl group, a chrysenyl group, a naphthacenylgroup, a picenyl group, a perylenyl group, a pentaphenyl group, ahexacenyl group, a pentacenyl group, a rubicenyl group, a coronenylgroup, an ovalenyl group, a pyrrolyl group, a thiophenyl group, afuranyl group, an imidazolyl group, a pyrazolyl group, a thiazolylgroup, an isothiazolyl group, an oxazolyl group, an isoxazolyl group, apyridinyl group, a pyrazinyl group, a pyrimidinyl group, a pyridazinylgroup, an isoindolyl group, an indolyl group, an indazolyl group, apurinyl group, a quinolinyl group, an isoquinolinyl group, abenzoquinolinyl group, a phthalazinyl group, a naphthyridinyl group, aquinoxalinyl group, a quinazolinyl group, a cinnolinyl group, acarbazolyl group, a phenanthridinyl group, an acridinyl group, aphenanthrolinyl group, a phenazinyl group, a benzoimidazolyl group, abenzofuranyl group, a benzothiophenyl group, an isobenzothiazolyl group,a benzoxazolyl group, an isobenzoxazolyl group, a triazolyl group, atetrazolyl group, an oxadiazolyl group, a triazinyl group, adibenzofuranyl group, a dibenzothiophenyl group, a benzocarbazolylgroup, a dibenzocarbazolyl group, an imidazopyridinyl group, or animidazopyrimidinyl group, each substituted with at least one of adeuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitrogroup, an amino group, an amidino group, a hydrazine group, a hydrazonegroup, a carboxylic acid group or a salt thereof, a sulfonic acid groupor a salt thereof, a phosphoric acid group or a salt thereof, a C₁-C₂₀alkyl group, a C₁-C₂₀ alkoxy group, a phenyl group, a pentalenyl group,an indenyl group, a naphthyl group, an azulenyl group, a heptalenylgroup, an indacenyl group, an acenaphthyl group, a fluorenyl group, aspiro-fluorenyl group, a benzofluorenyl group, a dibenzofluorenyl group,a phenalenyl group, a phenanthrenyl group, an anthracenyl group, afluoranthenyl group, a triphenylenyl group, a pyrenyl group, a chrysenylgroup, a naphthacenyl group, a picenyl group, a perylenyl group, apentaphenyl group, a hexacenyl group, a pentacenyl group, a rubicenylgroup, a coronenyl group, an ovalenyl group, a pyrrolyl group, athiophenyl group, a furanyl group, an imidazolyl group, a pyrazolylgroup, a thiazolyl group, an isothiazolyl group, an oxazolyl group, anisoxazolyl group, a pyridinyl group, a pyrazinyl group, a pyrimidinylgroup, a pyridazinyl group, an isoindolyl group, an indolyl group, anindazolyl group, a purinyl group, a quinolinyl group, an isoquinolinylgroup, a benzoquinolinyl group, a phthalazinyl group, a naphthyridinylgroup, a quinoxalinyl group, a quinazolinyl group, a cinnolinyl group, acarbazolyl group, a phenanthridinyl group, an acridinyl group, aphenanthrolinyl group, a phenazinyl group, a benzoimidazolyl group, abenzofuranyl group, a benzothiophenyl group, an isobenzothiazolyl group,a benzoxazolyl group, an isobenzoxazolyl group, a triazolyl group, atetrazolyl group, an oxadiazolyl group, a triazinyl group, adibenzofuranyl group, a dibenzothiophenyl group, a benzocarbazolylgroup, a dibenzocarbazolyl group, an imidazopyridinyl group, and animidazopyrimidinyl group, or

—Si(Q₁)(Q₂)(Q₃), wherein Q₁ to Q₃ may be each independently a hydrogen,a deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitrogroup, an amino group, an amidino group, a hydrazine group, a hydrazonegroup, a carboxylic acid group or a salt thereof, a sulfonic acid groupor a salt thereof, a phosphoric acid group or a salt thereof, a C₁-C₂₀alkyl group, a C₁-C₂₀ alkoxy group, a phenyl group, a naphthyl group, ananthracenyl group, a pyrenyl group, a phenanthrenyl group, a fluorenylgroup, a chrysenyl group, a carbazolyl group, a benzocarbazolyl group, adibenzocarbazolyl group, a dibenzofuranyl group, a dibenzothiophenylgroup, a pyridinyl group, a pyrimidinyl group, a triazinyl group, aquinolinyl group, an isoquinolinyl group, a quinazolinyl group, or aquinoxalinyl group.

In some other embodiments, Z₁ to Z₄, R₁ to R₄, R₁₁ to R₁₆, R₂₁, R₂₂, andQ₅₁ to Q₅₉ may be each independently

a hydrogen, a deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyanogroup, a nitro group, an amino group, an amidino group, a hydrazinegroup, a hydrazone group, a carboxylic acid group or a salt thereof, asulfonic acid group or a salt thereof, a phosphoric acid group or a saltthereof, a C₁-C₂₀ alkyl group, or a C₁-C₂₀ alkoxy group,

a C₁-C₂₀ alkyl group or a C₁-C₂₀ alkoxy group, each substituted with atleast one of a deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyanogroup, a nitro group, an amino group, an amidino group, a hydrazinegroup, a hydrazone group, a carboxylic acid group or a salt thereof, asulfonic acid group or a salt thereof, and a phosphoric acid group or asalt thereof,

a phenyl group, a naphthyl group, a fluorenyl group, a phenanthrenylgroup, an anthracenyl group, a fluoranthenyl group, a triphenylenylgroup, a pyrenyl group, a chrysenyl group, a pyrrolyl group, athiophenyl group, a furanyl group, an imidazolyl group, a pyrazolylgroup, a thiazolyl group, an isothiazolyl group, an oxazolyl group, anisoxazolyl group, a pyridinyl group, a pyrazinyl group, a pyrimidinylgroup, a pyridazinyl group, an isoindolyl group, an indolyl group, anindazolyl group, a purinyl group, a quinolinyl group, an isoquinolinylgroup, a benzoquinolinyl group, a quinoxalinyl group, a quinazolinylgroup, a cinnolinyl group, a carbazolyl group, a phenanthrolinyl group,a benzoimidazolyl group, a benzofuranyl group, a benzothiophenyl group,an isobenzothiazolyl group, a benzoxazolyl group, an isobenzoxazolylgroup, a triazolyl group, a tetrazolyl group, an oxadiazolyl group, atriazinyl group, a dibenzofuranyl group, a dibenzothiophenyl group, abenzocarbazolyl group, a dibenzocarbazolyl group, an imidazopyridinylgroup, or an imidazopyrimidinyl group,

a phenyl group, a naphthyl group, a fluorenyl group, a phenanthrenylgroup, an anthracenyl group, a fluoranthenyl group, a triphenylenylgroup, a pyrenyl group, a chrysenyl group, a pyrrolyl group, athiophenyl group, a furanyl group, an imidazolyl group, a pyrazolylgroup, a thiazolyl group, an isothiazolyl group, an oxazolyl group, anisoxazolyl group, a pyridinyl group, a pyrazinyl group, a pyrimidinylgroup, a pyridazinyl group, an isoindolyl group, an indolyl group, anindazolyl group, a purinyl group, a quinolinyl group, an isoquinolinylgroup, a benzoquinolinyl group, a quinoxalinyl group, a quinazolinylgroup, a cinnolinyl group, a carbazolyl group, a phenanthrolinyl group,a benzoimidazolyl group, a benzofuranyl group, a benzothiophenyl group,an isobenzothiazolyl group, a benzoxazolyl group, an isobenzoxazolylgroup, a triazolyl group, a tetrazolyl group, an oxadiazolyl group, atriazinyl group, a dibenzofuranyl group, a dibenzothiophenyl group, abenzocarbazolyl group, a dibenzocarbazolyl group, an imidazopyridinylgroup, or an imidazopyrimidinyl group, each substituted with at leastone of a deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, anitro group, an amino group, an amidino group, a hydrazine group, ahydrazone group, a carboxylic acid group or a salt thereof, a sulfonicacid group or a salt thereof, a phosphoric acid group or a salt thereof,a C₁-C₂₀ alkyl group, a C₁-C₂₀ alkoxy group, a phenyl group, a naphthylgroup, a fluorenyl group, a phenanthrenyl group, an anthracenyl group, afluoranthenyl group, a triphenylenyl group, a pyrenyl group, a chrysenylgroup, a pyrrolyl group, a thiophenyl group, a furanyl group, animidazolyl group, a pyrazolyl group, a thiazolyl group, an isothiazolylgroup, an oxazolyl group, an isoxazolyl group, a pyridinyl group, apyrazinyl group, a pyrimidinyl group, a pyridazinyl group, an isoindolylgroup, an indolyl group, an indazolyl group, a purinyl group, aquinolinyl group, an isoquinolinyl group, a benzoquinolinyl group, aquinoxalinyl group, a quinazolinyl group, a cinnolinyl group, acarbazolyl group, a phenanthrolinyl group, a benzoimidazolyl group, abenzofuranyl group, a benzothiophenyl group, an isobenzothiazolyl group,a benzoxazolyl group, an isobenzoxazolyl group, a triazolyl group, atetrazolyl group, an oxadiazolyl group, a triazinyl group, adibenzofuranyl group, a dibenzothiophenyl group, a benzocarbazolylgroup, a dibenzocarbazolyl group, an imidazopyridinyl group, and animidazopyrimidinyl group, or

—Si(Q₁)(Q₂)(Q₃), wherein Q₁ to Q₃ may be each independently a hydrogen,a deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitrogroup, an amino group, an amidino group, a hydrazine group, a hydrazonegroup, a carboxylic acid group or a salt thereof, a sulfonic acid groupor a salt thereof, a phosphoric acid group or a salt thereof, a C₁-C₂₀alkyl group, a C₁-C₂₀ alkoxy group, a phenyl group, a naphthyl group, apyridinyl group, a pyrimidinyl group, or a triazinyl group.

In some other embodiments, Z₁ to Z₄, R₁ to R₄, R₁ to R₁₆, R₂₁, R₂₂, andQ₅₁ to Q₅₉ may be each independently

a hydrogen, —F, a cyano group, a nitro group, a methyl group, an ethylgroup, n-propyl group, an isopropyl group, n-butyl group, an isobutylgroup, sec-butyl group, tert-butyl group, n-pentyl group, isopentylgroup, sec-pentyl group, tert-pentyl group, n-hexyl group, isohexylgroup, sec-hexyl group, tert-hexyl group, n-heptyl group, isoheptylgroup, sec-heptyl group, tert-heptyl group, n-octyl group, isooctylgroup, sec-octyl group, tert-octyl group, n-nonyl group, isononyl group,sec-nonyl group, tert-nonyl group, n-decyl group, isodecyl group,sec-decyl group, tert-decyl group, a methoxy group, an ethoxy group, apropoxy group, a butoxy group, a pentoxy group, a phenyl group, or anaphthyl group;

a methyl group, an ethyl group, a n-propyl group, an isopropyl group, an-butyl group, an isobutyl group, a sec-butyl group, a tert-butyl group,a n-pentyl group, an isopentyl group, a sec-pentyl group, a tert-pentylgroup, a n-hexyl group, an isohexyl group, a sec-hexyl group, atert-hexyl group, a n-heptyl group, an isoheptyl group, a sec-heptylgroup, a tert-heptyl group, a n-octyl group, an isooctyl group, asec-octyl group, a tert-octyl group, a n-nonyl group, an isononyl group,a sec-nonyl group, a tert-nonyl group, a n-decyl group, an isodecylgroup, a sec-decyl group, a tert-decyl group, a methoxy group, an ethoxygroup, a propoxy group, a butoxy group, a pentoxy group, a phenyl group,or a naphthyl group, each substituted with at least one of —F, a cyanogroup, and a nitro group, or

—Si(Q₁)(Q₂)(Q₃), wherein Q₁ to Q₃ may be each independently a hydrogen,a C₁-C₂₀ alkoxy group, a phenyl group, a naphthyl group, a pyridinylgroup, a pyrimidinyl group, or a triazinyl group.

In some embodiments, L₂ in Formula 1 may be a group represented by oneof Formulae 3-1 to 3-4 and Formulae 4-1 to 4-4:

In Formulae 3-1 to 3-4, and Formulae 4-1 to 4-4, Z₃, Z₄, R₁ to R₄, andR₁₁ to R₁₆ may be each independently the same as those defined above.

For example, in Formulae 3-1 to 3-4 and Formulae 4-1 to 4-4, Z₃, Z₄, R₁to R₄, and R₁₁ to R₁₆ may be each independently

a hydrogen, a deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyanogroup, a nitro group, an amino group, an amidino group, a hydrazinegroup, a hydrazone group, a carboxylic acid group or a salt thereof, asulfonic acid group or a salt thereof, a phosphoric acid group or a saltthereof, a C₁-C₂₀ alkyl group, or a C₁-C₂₀ alkoxy group,

a C₁-C₂₀ alkyl group or a C₁-C₂₀ alkoxy group, each substituted with atleast one of a deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyanogroup, a nitro group, an amino group, an amidino group, a hydrazinegroup, a hydrazone group, a carboxylic acid group or a salt thereof, asulfonic acid group or a salt thereof, and a phosphoric acid group or asalt thereof,

a phenyl group, a naphthyl group, a fluorenyl group, a phenanthrenylgroup, an anthracenyl group, a fluoranthenyl group, a triphenylenylgroup, a pyrenyl group, a chrysenyl group, a pyrrolyl group, athiophenyl group, a furanyl group, an imidazolyl group, a pyrazolylgroup, a thiazolyl group, an isothiazolyl group, an oxazolyl group, anisoxazolyl group, a pyridinyl group, a pyrazinyl group, a pyrimidinylgroup, a pyridazinyl group, an isoindolyl group, an indolyl group, anindazolyl group, a purinyl group, a quinolinyl group, an isoquinolinylgroup, a benzoquinolinyl group, a quinoxalinyl group, a quinazolinylgroup, a cinnolinyl group, a carbazolyl group, a phenanthrolinyl group,a benzoimidazolyl group, a benzofuranyl group, a benzothiophenyl group,an isobenzothiazolyl group, a benzoxazolyl group, an isobenzoxazolylgroup, a triazolyl group, a tetrazolyl group, an oxadiazolyl group, atriazinyl group, a dibenzofuranyl group, a dibenzothiophenyl group, abenzocarbazolyl group, a dibenzocarbazolyl group, an imidazopyridinylgroup, or an imidazopyrimidinyl group, or

a phenyl group, a naphthyl group, a fluorenyl group, a phenanthrenylgroup, an anthracenyl group, a fluoranthenyl group, a triphenylenylgroup, a pyrenyl group, a chrysenyl group, a pyrrolyl group, athiophenyl group, a furanyl group, an imidazolyl group, a pyrazolylgroup, a thiazolyl group, an isothiazolyl group, an oxazolyl group, anisoxazolyl group, a pyridinyl group, a pyrazinyl group, a pyrimidinylgroup, a pyridazinyl group, an isoindolyl group, an indolyl group, anindazolyl group, a purinyl group, a quinolinyl group, an isoquinolinylgroup, a benzoquinolinyl group, a quinoxalinyl group, a quinazolinylgroup, a cinnolinyl group, a carbazolyl group, a phenanthrolinyl group,a benzoimidazolyl group, a benzofuranyl group, a benzothiophenyl group,an isobenzothiazolyl group, a benzoxazolyl group, an isobenzoxazolylgroup, a triazolyl group, a tetrazolyl group, an oxadiazolyl group, atriazinyl group, a dibenzofuranyl group, a dibenzothiophenyl group, abenzocarbazolyl group, a dibenzocarbazolyl group, an imidazopyridinylgroup, or an imidazopyrimidinyl group, each substituted with at leastone of a deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, anitro group, an amino group, an amidino group, a hydrazine group, ahydrazone group, a carboxylic acid group or a salt thereof, a sulfonicacid group or a salt thereof, a phosphoric acid group or a salt thereof,a C₁-C₂₀ alkyl group, a C₁-C₂₀ alkoxy group, a phenyl group, a naphthylgroup, a fluorenyl group, a phenanthrenyl group, an anthracenyl group, afluoranthenyl group, a triphenylenyl group, a pyrenyl group, a chrysenylgroup, a pyrrolyl group, a thiophenyl group, a furanyl group, animidazolyl group, a pyrazolyl group, a thiazolyl group, an isothiazolylgroup, an oxazolyl group, an isoxazolyl group, a pyridinyl group, apyrazinyl group, a pyrimidinyl group, a pyridazinyl group, an isoindolylgroup, an indolyl group, an indazolyl group, a purinyl group, aquinolinyl group, an isoquinolinyl group, a benzoquinolinyl group, aquinoxalinyl group, a quinazolinyl group, a cinnolinyl group, acarbazolyl group, a phenanthrolinyl group, a benzoimidazolyl group, abenzofuranyl group, a benzothiophenyl group, an isobenzothiazolyl group,a benzoxazolyl group, an isobenzoxazolyl group, a triazolyl group, atetrazolyl group, an oxadiazolyl group, a triazinyl group, adibenzofuranyl group, a dibenzothiophenyl group, a benzocarbazolylgroup, a dibenzocarbazolyl group, an imidazopyridinyl group, and animidazopyrimidinyl group; and

* and *′ each indicates a binding site to M in Formula 1.

In some other embodiments, in Formulae 3-1 to 3-4 and Formulae 4-1 to4-4, Z₃, Z₄, R₁ to R₄, and R₁₁ to R₁₆ may be each independently

a hydrogen, —F, a cyano group, a nitro group, a methyl group, an ethylgroup, n-propyl group, an isopropyl group, a n-butyl group, an isobutylgroup, a sec-butyl group, a tert-butyl group, a n-pentyl group, anisopentyl group, a sec-pentyl group, a tert-pentyl group, a n-hexylgroup, an isohexyl group, a sec-hexyl group, a tert-hexyl group, an-heptyl group, an isoheptyl group, a sec-heptyl group, a tert-heptylgroup, a n-octyl group, an isooctyl group, a sec-octyl group, atert-octyl group, a n-nonyl group, an isononyl group, a sec-nonyl group,a tert-nonyl group, a n-decyl group, an isodecyl group, a sec-decylgroup, a tert-decyl group, a methoxy group, an ethoxy group, a propoxygroup, a butoxy group, a pentoxy group, a phenyl group, or a naphthylgroup, or

a methyl group, an ethyl group, a n-propyl group, an isopropyl group, an-butyl group, an isobutyl group, a sec-butyl group, a tert-butyl group,a n-pentyl group, an isopentyl group, a sec-pentyl group, a tert-pentylgroup, a n-hexyl group, an isohexyl group, a sec-hexyl group, atert-hexyl group, a n-heptyl group, an isoheptyl group, a sec-heptylgroup, a tert-heptyl group, a n-octyl group, an isooctyl group, asec-octyl group, a tert-octyl group, a n-nonyl group, an isononyl group,a sec-nonyl group, a tert-nonyl group, a n-decyl group, an isodecylgroup, a sec-decyl group, a tert-decyl group, a methoxy group, an ethoxygroup, a propoxy group, a butoxy group, a pentoxy group, a phenyl group,or a naphthyl group, each substituted with at least one of —F, a cyanogroup, and a nitro group. However, embodiments of the present inventiveconcept are not limited thereto.

In some embodiments, R₂₁ and R₂₂ in Formula 5 may be each independently

a cyano group or a C₁-C₂₀ alkoxy group,

a C₁-C₂₀ alkyl group or a C₁-C₂₀ alkoxy group, each substituted with atleast one of a deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyanogroup, a nitro group, an amino group, an amidino group, a hydrazinegroup, a hydrazone group, a carboxylic acid group or a salt thereof, asulfonic acid group or a salt thereof, and a phosphoric acid group or asalt thereof,

a phenyl group, a naphthyl group, a fluorenyl group, a phenanthrenylgroup, an anthracenyl group, a fluoranthenyl group, a triphenylenylgroup, a pyrenyl group, a chrysenyl group, a pyrrolyl group, athiophenyl group, a furanyl group, an imidazolyl group, a pyrazolylgroup, a thiazolyl group, an isothiazolyl group, an oxazolyl group, anisoxazolyl group, a pyridinyl group, a pyrazinyl group, a pyrimidinylgroup, a pyridazinyl group, an isoindolyl group, an indolyl group, anindazolyl group, a purinyl group, a quinolinyl group, an isoquinolinylgroup, a benzoquinolinyl group, a quinoxalinyl group, a quinazolinylgroup, a cinnolinyl group, a carbazolyl group, a phenanthrolinyl group,a benzoimidazolyl group, a benzofuranyl group, a benzothiophenyl group,an isobenzothiazolyl group, a benzoxazolyl group, an isobenzoxazolylgroup, a triazolyl group, a tetrazolyl group, an oxadiazolyl group, atriazinyl group, a dibenzofuranyl group, a dibenzothiophenyl group, abenzocarbazolyl group, a dibenzocarbazolyl group, an imidazopyridinylgroup, or an imidazopyrimidinyl group,

a phenyl group, a naphthyl group, a fluorenyl group, a phenanthrenylgroup, an anthracenyl group, a fluoranthenyl group, a triphenylenylgroup, a pyrenyl group, a chrysenyl group, a pyrrolyl group, athiophenyl group, a furanyl group, an imidazolyl group, a pyrazolylgroup, a thiazolyl group, an isothiazolyl group, an oxazolyl group, anisoxazolyl group, a pyridinyl group, a pyrazinyl group, a pyrimidinylgroup, a pyridazinyl group, an isoindolyl group, an indolyl group, anindazolyl group, a purinyl group, a quinolinyl group, an isoquinolinylgroup, a benzoquinolinyl group, a quinoxalinyl group, a quinazolinylgroup, a cinnolinyl group, a carbazolyl group, a phenanthrolinyl group,a benzoimidazolyl group, a benzofuranyl group, a benzothiophenyl group,an isobenzothiazolyl group, a benzoxazolyl group, an isobenzoxazolylgroup, a triazolyl group, a tetrazolyl group, an oxadiazolyl group, atriazinyl group, a dibenzofuranyl group, a dibenzothiophenyl group, abenzocarbazolyl group, a dibenzocarbazolyl group, an imidazopyridinylgroup, or an imidazopyrimidinyl group, each substituted with at leastone of a deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, anitro group, an amino group, an amidino group, a hydrazine group, ahydrazone group, a carboxylic acid group or a salt thereof, a sulfonicacid group or a salt thereof, a phosphoric acid group or a salt thereof,a C₁-C₂₀ alkyl group, a C₁-C₂₀ alkoxy group, a phenyl group, a naphthylgroup, a fluorenyl group, a phenanthrenyl group, an anthracenyl group, afluoranthenyl group, a triphenylenyl group, a pyrenyl group, a chrysenylgroup, a pyrrolyl group, a thiophenyl group, a furanyl group, animidazolyl group, a pyrazolyl group, a thiazolyl group, an isothiazolylgroup, an oxazolyl group, an isoxazolyl group, a pyridinyl group, apyrazinyl group, a pyrimidinyl group, a pyridazinyl group, an isoindolylgroup, an indolyl group, an indazolyl group, a purinyl group, aquinolinyl group, an isoquinolinyl group, a benzoquinolinyl group, aquinoxalinyl group, a quinazolinyl group, a cinnolinyl group, acarbazolyl group, a phenanthrolinyl group, a benzoimidazolyl group, abenzofuranyl group, a benzothiophenyl group, an isobenzothiazolyl group,a benzoxazolyl group, an isobenzoxazolyl group, a triazolyl group, atetrazolyl group, an oxadiazolyl group, a triazinyl group, adibenzofuranyl group, a dibenzothiophenyl group, a benzocarbazolylgroup, a dibenzocarbazolyl group, an imidazopyridinyl group, and animidazopyrimidinyl group, or

—Si(Q₁)(Q₂)(Q₃), wherein Q₁ to Q₃ may be each independently a hydrogen,a phenyl group, or a naphthyl group; and

at least one of R₂₁ and R₂₂ in Formula 5 may be

a cyano group or a C₁-C₂₀ alkoxy group,

a C₁-C₂₀ alkyl group or a C₁-C₂₀ alkoxy group, each substituted with atleast one of a deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyanogroup, a nitro group, an amino group, an amidino group, a hydrazinegroup, a hydrazone group, a carboxylic acid group or a salt thereof, asulfonic acid group or a salt thereof, and a phosphoric acid group or asalt thereof,

a naphthyl group, a fluorenyl group, a phenanthrenyl group, ananthracenyl group, a fluoranthenyl group, a triphenylenyl group, apyrenyl group, a chrysenyl group, a pyrrolyl group, a thiophenyl group,a furanyl group, an imidazolyl group, a pyrazolyl group, a thiazolylgroup, an isothiazolyl group, an oxazolyl group, an isoxazolyl group, apyridinyl group, a pyrazinyl group, a pyrimidinyl group, a pyridazinylgroup, an isoindolyl group, an indolyl group, an indazolyl group, apurinyl group, a quinolinyl group, an isoquinolinyl group, abenzoquinolinyl group, a quinoxalinyl group, a quinazolinyl group, acinnolinyl group, a carbazolyl group, a phenanthrolinyl group, abenzoimidazolyl group, a benzofuranyl group, a benzothiophenyl group, anisobenzothiazolyl group, a benzoxazolyl group, an isobenzoxazolyl group,a triazolyl group, a tetrazolyl group, an oxadiazolyl group, a triazinylgroup, a dibenzofuranyl group, a dibenzothiophenyl group, abenzocarbazolyl group, a dibenzocarbazolyl group, an imidazopyridinylgroup, or an imidazopyrimidinyl group, or

a phenyl group, a naphthyl group, a fluorenyl group, a phenanthrenylgroup, an anthracenyl group, a fluoranthenyl group, a triphenylenylgroup, a pyrenyl group, a chrysenyl group, a pyrrolyl group, athiophenyl group, a furanyl group, an imidazolyl group, a pyrazolylgroup, a thiazolyl group, an isothiazolyl group, an oxazolyl group, anisoxazolyl group, a pyridinyl group, a pyrazinyl group, a pyrimidinylgroup, a pyridazinyl group, an isoindolyl group, an indolyl group, anindazolyl group, a purinyl group, a quinolinyl group, an isoquinolinylgroup, a benzoquinolinyl group, a quinoxalinyl group, a quinazolinylgroup, a cinnolinyl group, a carbazolyl group, a phenanthrolinyl group,a benzoimidazolyl group, a benzofuranyl group, a benzothiophenyl group,an isobenzothiazolyl group, a benzoxazolyl group, an isobenzoxazolylgroup, a triazolyl group, a tetrazolyl group, an oxadiazolyl group, atriazinyl group, a dibenzofuranyl group, a dibenzothiophenyl group, abenzocarbazolyl group, a dibenzocarbazolyl group, an imidazopyridinylgroup, or an imidazopyrimidinyl group, each substituted with at leastone of a deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, anitro group, an amino group, an amidino group, a hydrazine group, ahydrazone group, a carboxylic acid group or a salt thereof, a sulfonicacid group or a salt thereof, a phosphoric acid group or a salt thereof,a C₁-C₂₀ alkoxy group, a phenyl group, a naphthyl group, a fluorenylgroup, a phenanthrenyl group, an anthracenyl group, a fluoranthenylgroup, a triphenylenyl group, a pyrenyl group, a chrysenyl group, apyrrolyl group, a thiophenyl group, a furanyl group, an imidazolylgroup, a pyrazolyl group, a thiazolyl group, an isothiazolyl group, anoxazolyl group, an isoxazolyl group, a pyridinyl group, a pyrazinylgroup, a pyrimidinyl group, a pyridazinyl group, an isoindolyl group, anindolyl group, an indazolyl group, a purinyl group, a quinolinyl group,an isoquinolinyl group, a benzoquinolinyl group, a quinoxalinyl group, aquinazolinyl group, a cinnolinyl group, a carbazolyl group, aphenanthrolinyl group, a benzoimidazolyl group, a benzofuranyl group, abenzothiophenyl group, an isobenzothiazolyl group, a benzoxazolyl group,an isobenzoxazolyl group, a triazolyl group, a tetrazolyl group, anoxadiazolyl group, a triazinyl group, a dibenzofuranyl group, adibenzothiophenyl group, a benzocarbazolyl group, a dibenzocarbazolylgroup, an imidazopyridinyl group, and an imidazopyrimidinyl group.

In some other embodiments, R₂₁ and R₂₂ in Formula 5 may be eachindependently

a cyano group or a C₁-C₂₀ alkoxy group,

a phenyl group, a naphthyl group, a phenanthrenyl group, an anthracenylgroup, a triphenylenyl group, a pyrrolyl group, a thiophenyl group, afuranyl group, an imidazolyl group, a pyrazolyl group, a pyridinylgroup, a pyrazinyl group, a pyrimidinyl group, a pyridazinyl group, anisoindolyl group, a purinyl group, a quinolinyl group, an isoquinolinylgroup, a quinoxalinyl group, a quinazolinyl group, a phenanthrolinylgroup, a benzoimidazolyl group, a benzofuranyl group, a benzothiophenylgroup, an isobenzothiazolyl group, a benzoxazolyl group, anisobenzoxazolyl group, a triazolyl group, a tetrazolyl group, anoxadiazolyl group, a triazinyl group, a dibenzofuranyl group, or adibenzothiophenyl group,

a phenyl group, a naphthyl group, a phenanthrenyl group, an anthracenylgroup, a triphenylenyl group, a pyrrolyl group, a thiophenyl group, afuranyl group, an imidazolyl group, a pyrazolyl group, a pyridinylgroup, a pyrazinyl group, a pyrimidinyl group, a pyridazinyl group, anisoindolyl group, a purinyl group, a quinolinyl group, an isoquinolinylgroup, a quinoxalinyl group, a quinazolinyl group, a phenanthrolinylgroup, a benzoimidazolyl group, a benzofuranyl group, a benzothiophenylgroup, an isobenzothiazolyl group, a benzoxazolyl group, anisobenzoxazolyl group, a triazolyl group, a tetrazolyl group, anoxadiazolyl group, a triazinyl group, a dibenzofuranyl group, or adibenzothiophenyl group, each substituted with at least one of adeuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitrogroup, an amino group, an amidino group, a hydrazine group, a hydrazonegroup, a carboxylic acid group or a salt thereof, a sulfonic acid groupor a salt thereof, a phosphoric acid group or a salt thereof, a C₁-C₂₀alkyl group, a C₁-C₂₀ alkoxy group, a phenyl group, a naphthyl group, aphenanthrenyl group, an anthracenyl group, a triphenylenyl group, apyrrolyl group, a thiophenyl group, a furanyl group, an imidazolylgroup, a pyrazolyl group, a pyridinyl group, a pyrazinyl group, apyrimidinyl group, a pyridazinyl group, an isoindolyl group, a purinylgroup, a quinolinyl group, an isoquinolinyl group, a quinoxalinyl group,a quinazolinyl group, a phenanthrolinyl group, a benzoimidazolyl group,a benzofuranyl group, a benzothiophenyl group, an isobenzothiazolylgroup, a benzoxazolyl group, an isobenzoxazolyl group, a triazolylgroup, a tetrazolyl group, an oxadiazolyl group, a triazinyl group, adibenzofuranyl group, and a dibenzothiophenyl group, or

—Si(Q₁)(Q₂)(Q₃), wherein Q₁ to Q₃ are each independently a hydrogen, aphenyl group, or a naphthyl group; and

at least one of R₂₁ and R₂₂ in Formula 5 may be

a cyano group or a C₁-C₂₀ alkoxy group,

a naphthyl group, a phenanthrenyl group, an anthracenyl group, atriphenylenyl group, a pyrrolyl group, a thiophenyl group, a furanylgroup, an imidazolyl group, a pyrazolyl group, a pyridinyl group, apyrazinyl group, a pyrimidinyl group, a pyridazinyl group, an isoindolylgroup, a purinyl group, a quinolinyl group, an isoquinolinyl group, aquinoxalinyl group, a quinazolinyl group, a phenanthrolinyl group, abenzoimidazolyl group, a benzofuranyl group, a benzothiophenyl group, anisobenzothiazolyl group, a benzoxazolyl group, an isobenzoxazolyl group,a triazolyl group, a tetrazolyl group, an oxadiazolyl group, a triazinylgroup, a dibenzofuranyl group, or a dibenzothiophenyl group, or

a phenyl group, a naphthyl group, a phenanthrenyl group, an anthracenylgroup, a triphenylenyl group, a pyrrolyl group, a thiophenyl group, afuranyl group, an imidazolyl group, a pyrazolyl group, a pyridinylgroup, a pyrazinyl group, a pyrimidinyl group, a pyridazinyl group, anisoindolyl group, a purinyl group, a quinolinyl group, an isoquinolinylgroup, a quinoxalinyl group, a quinazolinyl group, a phenanthrolinylgroup, a benzoimidazolyl group, a benzofuranyl group, a benzothiophenylgroup, an isobenzothiazolyl group, a benzoxazolyl group, anisobenzoxazolyl group, a triazolyl group, a tetrazolyl group, anoxadiazolyl group, a triazinyl group, a dibenzofuranyl group, or adibenzothiophenyl group, each substituted with at least one of adeuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitrogroup, an amino group, an amidino group, a hydrazine group, a hydrazonegroup, a carboxylic acid group or a salt thereof, a sulfonic acid groupor a salt thereof, a phosphoric acid group or a salt thereof, a C₁-C₂₀alkoxy group, a phenyl group, a naphthyl group, a phenanthrenyl group,an anthracenyl group, a triphenylenyl group, a pyrrolyl group, athiophenyl group, a furanyl group, an imidazolyl group, a pyrazolylgroup, a pyridinyl group, a pyrazinyl group, a pyrimidinyl group, apyridazinyl group, an isoindolyl group, a purinyl group, a quinolinylgroup, an isoquinolinyl group, a quinoxalinyl group, a quinazolinylgroup, a phenanthrolinyl group, a benzoimidazolyl group, a benzofuranylgroup, a benzothiophenyl group, an isobenzothiazolyl group, abenzoxazolyl group, an isobenzoxazolyl group, a triazolyl group, atetrazolyl group, an oxadiazolyl group, a triazinyl group, adibenzofuranyl group, and a dibenzothiophenyl group. However,embodiments of the present inventive concept are not limited thereto.

In some embodiments, L₂ in Formula 1 is a group represented by Formula5A or 5B:

In Formulae 5A and 5B,

Z₃, Z₄, Z₃₂, and b2 may be the same as those defined in claim 1;

X₃₁ may be N or CR₃₁;

X₃₂ may be N or CR₃₂;

X₃₃ may be N or CR₃₃;

X₃₄ may be N or CR₃₄;

X₃₅ may be N or CR₃₅;

X₃₆ may be N or CR₃₆;

X₃₇ may be N or CR₃₇;

X₃₈ may be N or CR₃₈;

at least one of X₃₁ to X₃₈ may be N; and

R₃₁ to R₃₈ are the same or different and may each have the samedefinition as R₁.

For example, R₃₁ to R₃₈ in Formulae 5A and 5B may be each independently

a hydrogen, —F, a cyano group, a nitro group, a methyl group, an ethylgroup, a n-propyl group, an isopropyl group, a n-butyl group, anisobutyl group, a sec-butyl group, a tert-butyl group, a n-pentyl group,an isopentyl group, a sec-pentyl group, a tert-pentyl group, a n-hexylgroup, an isohexyl group, a sec-hexyl group, a tert-hexyl group, an-heptyl group, an isoheptyl group, a sec-heptyl group, a tert-heptylgroup, a n-octyl group, an isooctyl group, a sec-octyl group, atert-octyl group, a n-nonyl group, an isononyl group, a sec-nonyl group,a tert-nonyl group, a n-decyl group, an isodecyl group, a sec-decylgroup, a tert-decyl group, a methoxy group, an ethoxy group, a propoxygroup, a butoxy group, a pentoxy group, a phenyl group, or a naphthylgroup, or

a methyl group, an ethyl group, a n-propyl group, an isopropyl group, an-butyl group, an isobutyl group, a sec-butyl group, a tert-butyl group,a n-pentyl group, an isopentyl group, a sec-pentyl group, a tert-pentylgroup, a n-hexyl group, an isohexyl group, a sec-hexyl group, atert-hexyl group, a n-heptyl group, an isoheptyl group, a sec-heptylgroup, a tert-heptyl group, a n-octyl group, an isooctyl group, asec-octyl group, a tert-octyl group, a n-nonyl group, an isononyl group,a sec-nonyl group, a tert-nonyl group, a n-decyl group, an isodecylgroup, a sec-decyl group, a tert-decyl group, a methoxy group, an ethoxygroup, a propoxy group, a butoxy group, a pentoxy group, a phenyl group,or a naphthyl group, each substituted with at least one of —F, a cyanogroup, and a nitro group. However, embodiments of the present inventiveconcept are not limited thereto.

In some embodiments, L₂ in Formula 1 may be selected from groupsrepresented by Formulae 5-1 to 5-25. However, embodiments of the presentinventive concept are not limited thereto.

In Formulae 5-1 to 5-25, Z₃, Z₄, R₃₁ to R₃₈, and Q₅₂ to Q₅₅ may be thesame as those defined above.

For example, in Formulae 5-1 to 5-25, Z₃, Z₄, R₃₁ to R₃₈, and Q₅₂ to Q₅₅may be each independently

a hydrogen, a deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyanogroup, a nitro group, an amino group, an amidino group, a hydrazinegroup, a hydrazone group, a carboxylic acid group or a salt thereof, asulfonic acid group or a salt thereof, a phosphoric acid group or a saltthereof, a C₁-C₂₀ alkyl group, or a C₁-C₂₀ alkoxy group,

a C₁-C₂₀ alkyl group or a C₁-C₂₀ alkoxy group, each substituted with atleast one of a deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyanogroup, a nitro group, an amino group, an amidino group, a hydrazinegroup, a hydrazone group, a carboxylic acid group or a salt thereof, asulfonic acid group or a salt thereof, and a phosphoric acid group or asalt thereof,

a phenyl group, a naphthyl group, a fluorenyl group, a phenanthrenylgroup, an anthracenyl group, a fluoranthenyl group, a triphenylenylgroup, a pyrenyl group, a chrysenyl group, a pyrrolyl group, athiophenyl group, a furanyl group, an imidazolyl group, a pyrazolylgroup, a thiazolyl group, an isothiazolyl group, an oxazolyl group, anisoxazolyl group, a pyridinyl group, a pyrazinyl group, a pyrimidinylgroup, a pyridazinyl group, an isoindolyl group, an indolyl group, anindazolyl group, a purinyl group, a quinolinyl group, an isoquinolinylgroup, a benzoquinolinyl group, a quinoxalinyl group, a quinazolinylgroup, a cinnolinyl group, a carbazolyl group, a phenanthrolinyl group,a benzoimidazolyl group, a benzofuranyl group, a benzothiophenyl group,an isobenzothiazolyl group, a benzoxazolyl group, an isobenzoxazolylgroup, a triazolyl group, a tetrazolyl group, an oxadiazolyl group, atriazinyl group, a dibenzofuranyl group, a dibenzothiophenyl group, abenzocarbazolyl group, a dibenzocarbazolyl group, an imidazopyridinylgroup, or an imidazopyrimidinyl group, or

a phenyl group, a naphthyl group, a fluorenyl group, a phenanthrenylgroup, an anthracenyl group, a fluoranthenyl group, a triphenylenylgroup, a pyrenyl group, a chrysenyl group, a pyrrolyl group, athiophenyl group, a furanyl group, an imidazolyl group, a pyrazolylgroup, a thiazolyl group, an isothiazolyl group, an oxazolyl group, anisoxazolyl group, a pyridinyl group, a pyrazinyl group, a pyrimidinylgroup, a pyridazinyl group, an isoindolyl group, an indolyl group, anindazolyl group, a purinyl group, a quinolinyl group, an isoquinolinylgroup, a benzoquinolinyl group, a quinoxalinyl group, a quinazolinylgroup, a cinnolinyl group, a carbazolyl group, a phenanthrolinyl group,a benzoimidazolyl group, a benzofuranyl group, a benzothiophenyl group,an isobenzothiazolyl group, a benzoxazolyl group, an isobenzoxazolylgroup, a triazolyl group, a tetrazolyl group, an oxadiazolyl group, atriazinyl group, a dibenzofuranyl group, a dibenzothiophenyl group, abenzocarbazolyl group, a dibenzocarbazolyl group, an imidazopyridinylgroup, or an imidazopyrimidinyl group, each substituted with at leastone of a deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, anitro group, an amino group, an amidino group, a hydrazine group, ahydrazone group, a carboxylic acid group or a salt thereof, a sulfonicacid group or a salt thereof, a phosphoric acid group or a salt thereof,a C₁-C₂₀ alkyl group, a C₁-C₂₀ alkoxy group, a phenyl group, a naphthylgroup, a fluorenyl group, a phenanthrenyl group, an anthracenyl group, afluoranthenyl group, a triphenylenyl group, a pyrenyl group, a chrysenylgroup, a pyrrolyl group, a thiophenyl group, a furanyl group, animidazolyl group, a pyrazolyl group, a thiazolyl group, an isothiazolylgroup, an oxazolyl group, an isoxazolyl group, a pyridinyl group, apyrazinyl group, a pyrimidinyl group, a pyridazinyl group, an isoindolylgroup, an indolyl group, an indazolyl group, a purinyl group, aquinolinyl group, an isoquinolinyl group, a benzoquinolinyl group, aquinoxalinyl group, a quinazolinyl group, a cinnolinyl group, acarbazolyl group, a phenanthrolinyl group, a benzoimidazolyl group, abenzofuranyl group, a benzothiophenyl group, an isobenzothiazolyl group,a benzoxazolyl group, an isobenzoxazolyl group, a triazolyl group, atetrazolyl group, an oxadiazolyl group, a triazinyl group, adibenzofuranyl group, a dibenzothiophenyl group, a benzocarbazolylgroup, a dibenzocarbazolyl group, an imidazopyridinyl group, and animidazopyrimidinyl group;

d1 may be an integer selected from 1 to 4;

d2 may be an integer selected from 1 to 5;

d3 may be an integer selected from 1 to 3;

d4 may be 1 or 2; and

d5 may be an integer selected from 1 to 7.

In some other embodiments, in Formulae 5-1 to 5-25, Z₃, Z₄, R₃₁ to R₃₈,and Q₅₂ to Q₅₅ may be each independently

a hydrogen, —F, a cyano group, a nitro group, a methyl group, an ethylgroup, a n-propyl group, an isopropyl group, a n-butyl group, anisobutyl group, a sec-butyl group, a tert-butyl group, a n-pentyl group,an isopentyl group, a sec-pentyl group, a tert-pentyl group, a n-hexylgroup, an isohexyl group, a sec-hexyl group, a tert-hexyl group, an-heptyl group, an isoheptyl group, a sec-heptyl group, a tert-heptylgroup, a n-octyl group, an isooctyl group, a sec-octyl group, atert-octyl group, a n-nonyl group, an isononyl group, a sec-nonyl group,a tert-nonyl group, a n-decyl group, an isodecyl group, a sec-decylgroup, a tert-decyl group, a methoxy group, an ethoxy group, a propoxygroup, a butoxy group, a pentoxy group, a phenyl group, or a naphthylgroup, or

a methyl group, an ethyl group, a n-propyl group, an isopropyl group, an-butyl group, an isobutyl group, a sec-butyl group, a tert-butyl group,a n-pentyl group, an isopentyl group, a sec-pentyl group, a tert-pentylgroup, a n-hexyl group, an isohexyl group, a sec-hexyl group, atert-hexyl group, a n-heptyl group, an isoheptyl group, a sec-heptylgroup, a tert-heptyl group, a n-octyl group, an isooctyl group, asec-octyl group, a tert-octyl group, a n-nonyl group, an isononyl group,a sec-nonyl group, a tert-nonyl group, a n-decyl group, an isodecylgroup, a sec-decyl group, a tert-decyl group, a methoxy group, an ethoxygroup, a propoxy group, a butoxy group, a pentoxy group, a phenyl group,or a naphthyl group, each substituted with at least one of —F, a cyanogroup, and a nitro group. However, embodiments of the present inventiveconcept are not limited thereto.

In some embodiments, in Formula 2,

CY₁ may be a pyridine or an imidazole;

CY₂ may be a benzene, a pyridine, or a dibenzofuran;

Z₁ and Z₂ may be each independently

a hydrogen, —F, a cyano group, a nitro group, a methyl group, an ethylgroup, a n-propyl group, an isopropyl group, a n-butyl group, anisobutyl group, a sec-butyl group, a tert-butyl group, a n-pentyl group,an isopentyl group, a sec-pentyl group, a tert-pentyl group, a n-hexylgroup, an isohexyl group, a sec-hexyl group, a tert-hexyl group, an-heptyl group, an isoheptyl group, a sec-heptyl group, a tert-heptylgroup, a n-octyl group, an isooctyl group, a sec-octyl group, atert-octyl group, a n-nonyl group, an isononyl group, a sec-nonyl group,a tert-nonyl group, a n-decyl group, an isodecyl group, a sec-decylgroup, a tert-decyl group, a methoxy group, an ethoxy group, a propoxygroup, a butoxy group, a pentoxy group, a phenyl group, or a naphthylgroup, or

a methyl group, an ethyl group, a n-propyl group, an isopropyl group, an-butyl group, an isobutyl group, a sec-butyl group, a tert-butyl group,a n-pentyl group, an isopentyl group, a sec-pentyl group, a tert-pentylgroup, a n-hexyl group, an isohexyl group, a sec-hexyl group, atert-hexyl group, a n-heptyl group, an isoheptyl group, a sec-heptylgroup, a tert-heptyl group, a n-octyl group, an isooctyl group, asec-octyl group, a tert-octyl group, a n-nonyl group, an isononyl group,a sec-nonyl group, a tert-nonyl group, a n-decyl group, an isodecylgroup, a sec-decyl group, a tert-decyl group, a methoxy group, an ethoxygroup, a propoxy group, a butoxy group, a pentoxy group, a phenyl group,or a naphthyl group, each substituted with at least one of —F, a cyanogroup, and a nitro group; and

L₂ in Formula 1 may be a ligand represented by one of Formulae 3-1 to3-4, Formulae 4-1 to 4-4, and Formulae 5-1 to 5-25.

In some embodiments,

L₁ in Formula 1 may be a ligand represented by one of Formulae 2-1 to2-90, and L₂ in Formula 1 may be a ligand represented by one of Formulae3-1 to 3-4, Formulae 4-1 to 4-4, and Formulae 5-1 to 5-25.

In some other embodiments, L₁ in Formula 1 may be a ligand representedby one of Formulae 2-1A, 2-2A, 2-70A, and 2-87A, and L₂ in Formula 1 maybe a ligand represented by one of Formulae 3-1 to 3-4, Formulae 4-1 to4-4, and Formulae 5-1 to 5-25.

In Formula 2, a1 and a2, which indicate the number of groups Z₁ and thenumber of groups Z₂, respectively, may be each independently an integerof 0 to 5. For example, a1 may be 0, 1, or 2, and a2 may be 0, 1, 2, or3.

When a1 is 2 or greater, a1 number of groups Z₁ may be identical to ordifferent from each other. When a2 is 2 or greater, a2 number of groupsZ₂ may be identical to or different from each other.

In Formula 1, n1 and n2 may be each independently 1 or 2.

For example, in Formula 1, M may be Ir; n1 may be 1; and n2 may be 2. Insome other embodiments, n1 may be 2, and n2 may be 1.

In some embodiments, the organometallic compound of Formula 1 may be oneof Compounds 1 to 56:

In Formula 1, L₁ may be a ligand represented by Formula 2 as describedabove. Thus, an organic light-emitting device including theorganometallic compound of Formula 1 may have an improved emissionefficiency.

In Formula 1, L₂ may be one of the ligands represented by Formulae 3 to5 as described above,

As described above, X₁ to X₄ in Formula 3 may be each independentlynitrogen (N), and at least one of X₁₁ to X₁₆ in Formula 4 may be N.Thus, an organometallic compound including a ligand represented byFormula 3 and 4 may have improved electron mobility and improvedelectron transport ability. Thus, an organic light-emitting deviceincluding the organometallic compound of Formula 1, wherein L₂ is aligand represented by Formula 3 or 4, may have an improved emissionefficiency.

In Formula 5, the following conditions regarding R₂₁ and R₂₂ areexcluded:

i) where R₂₁ and R₂₂ are both phenyl groups,

ii) where R₂₁ and R₂₂ are both phenyl groups substituted with atert-butyl group,

iii) where R₂₁ and R₂₂ are both ethyl groups,

iv) where R₂₁ and R₂₂ are both propyl groups,

v) where R₂₁ and R₂₂ are both butyl groups, and

vi) where R₂₁ and R₂₂ are both —Si(CH₃)₃.

For example, at least one of R₂₁ and R₂₂ in Formula 5 may be

a cyano group or a C₁-C₂₀ alkoxy group,

a C₁-C₂₀ alkyl group or a C₁-C₂₀ alkoxy group, each substituted with atleast one of a deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyanogroup, a nitro group, an amino group, an amidino group, a hydrazinegroup, a hydrazone group, a carboxylic acid group or a salt thereof, asulfonic acid group or a salt thereof, and a phosphoric acid group or asalt thereof,

a naphthyl group, a fluorenyl group, a phenanthrenyl group, ananthracenyl group, a fluoranthenyl group, a triphenylenyl group, apyrenyl group, a chrysenyl group, a pyrrolyl group, a thiophenyl group,a furanyl group, an imidazolyl group, a pyrazolyl group, a thiazolylgroup, an isothiazolyl group, an oxazolyl group, an isoxazolyl group, apyridinyl group, a pyrazinyl group, a pyrimidinyl group, a pyridazinylgroup, an isoindolyl group, an indolyl group, an indazolyl group, apurinyl group, a quinolinyl group, an isoquinolinyl group, abenzoquinolinyl group, a quinoxalinyl group, a quinazolinyl group, acinnolinyl group, a carbazolyl group, a phenanthrolinyl group, abenzoimidazolyl group, a benzofuranyl group, a benzothiophenyl group, anisobenzothiazolyl group, a benzoxazolyl group, an isobenzoxazolyl group,a triazolyl group, a tetrazolyl group, an oxadiazolyl group, a triazinylgroup, a dibenzofuranyl group, a dibenzothiophenyl group, abenzocarbazolyl group, a dibenzocarbazolyl group, an imidazopyridinylgroup, or an imidazopyrimidinyl group,

a phenyl group, a naphthyl group, a fluorenyl group, a phenanthrenylgroup, an anthracenyl group, a fluoranthenyl group, a triphenylenylgroup, a pyrenyl group, a chrysenyl group, a pyrrolyl group, athiophenyl group, a furanyl group, an imidazolyl group, a pyrazolylgroup, a thiazolyl group, an isothiazolyl group, an oxazolyl group, anisoxazolyl group, a pyridinyl group, a pyrazinyl group, a pyrimidinylgroup, a pyridazinyl group, an isoindolyl group, an indolyl group, anindazolyl group, a purinyl group, a quinolinyl group, an isoquinolinylgroup, a benzoquinolinyl group, a quinoxalinyl group, a quinazolinylgroup, a cinnolinyl group, a carbazolyl group, a phenanthrolinyl group,a benzoimidazolyl group, a benzofuranyl group, a benzothiophenyl group,an isobenzothiazolyl group, a benzoxazolyl group, an isobenzoxazolylgroup, a triazolyl group, a tetrazolyl group, an oxadiazolyl group, atriazinyl group, a dibenzofuranyl group, a dibenzothiophenyl group, abenzocarbazolyl group, a dibenzocarbazolyl group, an imidazopyridinylgroup, or an imidazopyrimidinyl group, each substituted with at leastone of a deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, anitro group, an amino group, an amidino group, a hydrazine group, ahydrazone group, a carboxylic acid group or a salt thereof, a sulfonicacid group or a salt thereof, a phosphoric acid group or a salt thereof,a C₁-C₂₀ alkoxy group, a phenyl group, a naphthyl group, a fluorenylgroup, a phenanthrenyl group, an anthracenyl group, a fluoranthenylgroup, a triphenylenyl group, a pyrenyl group, a chrysenyl group, apyrrolyl group, a thiophenyl group, a furanyl group, an imidazolylgroup, a pyrazolyl group, a thiazolyl group, an isothiazolyl group, anoxazolyl group, an isoxazolyl group, a pyridinyl group, a pyrazinylgroup, a pyrimidinyl group, a pyridazinyl group, an isoindolyl group, anindolyl group, an indazolyl group, a purinyl group, a quinolinyl group,an isoquinolinyl group, a benzoquinolinyl group, a quinoxalinyl group, aquinazolinyl group, a cinnolinyl group, a carbazolyl group, aphenanthrolinyl group, a benzoimidazolyl group, a benzofuranyl group, abenzothiophenyl group, an isobenzothiazolyl group, a benzoxazolyl group,an isobenzoxazolyl group, a triazolyl group, a tetrazolyl group, anoxadiazolyl group, a triazinyl group, a dibenzofuranyl group, adibenzothiophenyl group, a benzocarbazolyl group, a dibenzocarbazolylgroup, an imidazopyridinyl group, and an imidazopyrimidinyl group, or

—Si(Q₁)(Q₂)(Q₃), wherein Q₁ to Q₃ may be each independently selectedfrom a hydrogen, a phenyl group, and a naphthyl group.

An organometallic compound including the ligand of Formula 5 may haveimproved electron mobility and improved electron transport ability.Thus, an organic light-emitting device including the organometalliccompound of Formula 1, wherein L₂ is a ligand of Formula 5, may haveimproved emission efficiency.

For example, the organometallic compound of Formula 1 may emit deep bluelight having a peak emission wavelength of about 435 nanometers (nm) toabout 500 nm, an x-color coordinate of about 0.14 to about 0.25, forexample, about 0.16 to about 0.23, and a y-color coordinate of about0.10 to about 0.41, for example, about 0.25 to about 0.35.

A synthesis method of the organometallic compound of Formula 1 above maybe easily understood to one of ordinary skill in the art based on thesynthesis examples described below.

As described above, the organometallic compound of Formula 1 above maybe appropriate for use as a material for the organic layer, for example,a dopant of the EML.

According to another embodiment of the present disclosure, an organiclight-emitting device includes

a first electrode,

a second electrode, and

an organic layer disposed between the first electrode and the secondelectrode,

wherein the organic layer includes an EML and at least one of theorganometallic compounds of Formula 1 above.

Due to the inclusion of the organic layer including the organometalliccompound of Formula 1 described above, the organic light-emitting devicemay have a low driving voltage, a high efficiency, and a long lifetime.

The organometallic compound of Formula 1 above may be used between apair of electrodes of an organic light-emitting device. For example, theorganometallic compound of Formula 1 may be included in the EML. In thisregard, the organometallic compound of Formula 1 may serve as a dopantin the EML, and the EML may further include a host. The EML may emit redlight, green light, or blue light.

As used herein, the phrase “(for example, the organic layer) includingat least one organometallic compound means that “(the organic layer)including one of the organometallic compounds of Formula 1 above, or atleast two different organometallic compounds of Formula 1 above”.

For example, the organic layer of the organic light-emitting device mayinclude only Compound 1 as the organometallic compound. For example,Compound 1 may be included in the EML of the organic light-emittingdevice. In some embodiments, the organic layer of the organiclight-emitting device may include Compounds 1 and 2 as theorganometallic compound. For example, Compounds 1 and 2 may be includedboth in the EML.

The first electrode may be an anode as a hole injection electrode, andthe second electrode may be a cathode as an electron injectionelectrode. In some embodiments, the first electrode may be a cathode asan electron injection electrode, and the second electrode may be ananode as a hole injection electrode.

For example, the first electrode may be an anode, the second electrodemay be a cathode, and the organic layer may include:

i) a hole transport region disposed between the first electrode and theemission layer and including at least one of a hole injection layer, ahole transport layer, and an electron blocking layer; and

ii) an electron transport region disposed between the emission layer andthe second electrode and including at least one of a hole blockinglayer, an electron transport layer, and an electron injection layer.

The term “organic layer” as used herein refers to a single layer and/ora plurality of layers disposed between the first and second electrodesof the organic light-emitting device. The “organic layer” may include,for example, an organic compound or an organometallic complex includinga metal.

FIG. 1 is a schematic view of an organic light-emitting device 10according to an embodiment of the present disclosure. Hereinafter, astructure of an organic light-emitting device according to an embodimentof the present disclosure and a method of manufacturing the same willnow be described with reference to FIG. 1. Referring to FIG. 1, theorganic light-emitting device 10 has a structure in which a substrate11, a first electrode 11, an organic layer 15, and a second electrode 19are sequentially stacked in this order.

A substrate (not shown) may be disposed under the first electrode 11 oron the second electrode 190 in FIG. 1. The substrate may be anysubstrate that is used in conventional organic light emitting devices.In some embodiments the substrate may be a glass substrate or atransparent plastic substrate with strong mechanical strength, thermalstability, transparency, surface smoothness, ease of handling, and waterresistance.

The first electrode 11 may be formed by depositing or sputtering a firstelectrode-forming material on the substrate 11. The first electrode 11may be an anode. A material having a high work function may be selectedas a material for the first electrode to facilitate hole injection. Thefirst electrode 11 may be a reflective electrode, a semi-transmissiveelectrode, or a transmissive electrode. For example, the material forthe first electrode 13 may be indium tin oxide (ITO), indium zinc oxide(IZO), tin oxide (SnO₂), or zinc oxide (ZnO). In some embodiments, thematerial for the first electrode 13 may be metals, for example,magnesium (Mg), aluminum (Al), aluminum-lithium (Al—Li), calcium (Ca),magnesium-indium (Mg—In), magnesium-silver (Mg—Ag), or the like.

The first electrode 11 may have a single-layer structure or amulti-layer structure including at least two layers. For example, thefirst electrode 11 may have, but not limited to, a three-layeredstructure including ITO, Ag, and ITO layers.

The organic layer 15 may be disposed on the first electrode 11.

The organic layer 15 may include at least one a hole transport region;an EML, and an electron transport region.

The hole transport region may be disposed between the first electrode 11and the EML.

The hole transport region may include at least one of a hole injectionlayer (HIL), a hole transport layer (HTL), an electron blocking layer(EBL), and a buffer layer.

The hole transport region may include exclusively the HIL or the HTL. Insome embodiments, the electron transport region may have a structureincluding a HIL/HTL or a HIL/HTL/EBL, wherein the layers forming thestructure of the electron transport region may be sequentially stackedon the first electrode 10 in the stated order.

When the hole transport region includes the HIL, the HIL may be formedon the first electrode 11 by any of a variety of methods, for example,vacuum deposition, spin coating, casting, Langmuir-Blodgett (LB)deposition, or the like.

When the HIL is formed using vacuum deposition, vacuum depositionconditions may vary depending on the material that is used to form theHIL, and the desired structure and thermal properties of the HIL to beformed. For example, vacuum deposition may be performed at a temperatureof about 100° C. to about 500° C., a pressure of about 10⁻⁸ torr toabout 10⁻³ torr, and a deposition rate of about 0.01 to about 100Angstroms per second (Å/sec). However, the deposition conditions are notlimited thereto.

When the HIL is formed using spin coating, the coating conditions mayvary depending on the material that is used to form the HIL, and thedesired structure and thermal properties of the HIL to be formed. Forexample, the coating rate may be in the range of about 2,000 revolutionsper minute (rpm) to about 5,000 rpm, and a temperature at which heattreatment is performed to remove a solvent after coating may be in arange of about 80° to about 200° C. However, the coating conditions arenot limited thereto.

Conditions for forming the HTL and the EBL may be the same as those forthe HIL described above.

In some embodiments, the hole transport region may include at least oneof m-MTDATA, TDATA, 2-TNATA, NPB, β-NPB, TPD, Spiro-TPD, Spiro-NPB,methylated-NPB, TAPC, HMTPD, 4,4′,4″-tris(N-carbazolyl)triphenylamine(TCTA), polyaniline/dodecylbenzene sulfonic acid (Pani/DBSA),poly(3,4-ethylenedioxythiophene)/poly(4-styrenesulfonate)(PEDOT/PSS),polyaniline/camphor sulfonic acid (Pani/CSA),polyaniline/poly(4-styrenesulfonate) (PANI/PSS), a compound representedby Formula 201 below, and a compound represented by Formula 202 below.

In Formula 201 above, Ar₁₀₁ and Ar₁₀₂ may be each independently

a phenylene group, a pentalenylene group, an indenylene group, anaphthylene group, an azulenylene group, a heptalenylene group, anacenaphthylene group, a fluorenylene group, a phenalenylene group, aphenanthrenylene group, an anthracenylene group, a fluoranthenylenegroup, a triphenylenylene group, a pyrenylene group, a chrysenylenegroup, a naphthacenylene group, a picenylene group, a perylenylenegroup, or a pentacenylene group, or

a phenylene group, a pentalenylene group, an indenylene group, anaphthylene group, an azulenylene group, a heptalenylene group, anacenaphthylene group, a fluorenylene group, a phenalenylene group, aphenanthrenylene group, an anthracenylene group, a fluoranthenylenegroup, a triphenylenylene group, a pyrenylene group, a chrysenylenegroup, a naphthacenylene group, a picenylene group, a perylenylenegroup, or a pentacenylene group, each substituted with at least one of adeuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitrogroup, an amino group, an amidino group, a hydrazine group, a hydrazonegroup, a carboxylic acid group or a salt thereof, a sulfonic acid groupor a salt thereof, a phosphoric acid group or a salt thereof, a C₁-C₆₀alkyl group, a C₂-C₆₀ alkenyl group, a C₂-C₆₀ alkynyl group, a C₁-C₆₀alkoxy group, a C₃-C₁₀ cycloalkyl group, a C₃-C₁₀ cycloalkenyl group, aC₂-C₁₀ heterocycloalkyl group, a C₂-C₁₀ heterocycloalkenyl group, aC₆-C₆₀ aryl group, a C₆-C₆₀ aryloxy group, a C₆-C₆₀ arylthio group, aC₂-C₆₀ heteroaryl group, a monovalent non-aromatic condensed polycyclicgroup, and a monovalent non-aromatic condensed heteropolycyclic group.

In Formula 201, xa and xb may be each independently an integer from 0 to5, for example, may be 0, 1, or 2. For example, xa may be 1, and xb maybe 0, but are not limited thereto.

In Formulae 201 and 202, R₁₀₁ to R₁₀₈, R₁₁₁ to R₁₁₉, and R₁₂₁ to R₁₂₄may be each independently

a hydrogen, a deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyanogroup, a nitro group, an amino group, an amidino group, a hydrazinegroup, a hydrazone group, a carboxylic acid group or a salt thereof, asulfonic acid group or a salt thereof, a phosphoric acid group or a saltthereof, a C₁-C₁₀ alkyl group (for example, a methyl group, an ethylgroup, a propyl group, a butyl group, a pentyl group, a hexyl group, orthe like), or a C₁-C₁₀ alkoxy group (for example, a methoxy group, anethoxy group, a propoxy group, a butoxy group, a pentoxy group, or thelike),

a C₁-C₁₀ alkyl group or a C₁-C₁₀ alkoxy group, each substituted with atleast one of a deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyanogroup, a nitro group, an amino group, an amidino group, a hydrazinegroup, a hydrazone group, a carboxylic acid group or a salt thereof, asulfonic acid group or a salt thereof, and a phosphoric acid group or asalt thereof,

a phenyl group, a naphthyl group, an anthracenyl group, a fluorenylgroup, or a pyrenyl group, or

a phenyl group, a naphthyl group, an anthracenyl group, a fluorenylgroup, or a pyrenyl group, each substituted with at least one of adeuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitrogroup, an amino group, an amidino group, a hydrazine group, a hydrazonegroup, a carboxylic acid group or a salt thereof, a sulfonic acid groupor a salt thereof, a phosphoric acid group or a salt thereof, a C₁-C₁₀alkyl group, and a C₁-C₁₀ alkoxy group. However, embodiments of thepresent disclosure are not limited thereto.

In Formula 201 above, R₁₀₉ may be

a phenyl group, a naphthyl group, an anthracenyl group, or a pyridinylgroup, or

a phenyl group, a naphthyl group, an anthracenyl group, or a pyridinylgroup, each substituted with at least one of a deuterium, —F, —Cl, —Br,—I, a hydroxyl group, a cyano group, a nitro group, an amino group, anamidino group, a hydrazine group, a hydrazone group, a carboxylic acidgroup or a salt thereof, a sulfonic acid group or a salt thereof, aphosphoric acid group or a salt thereof, a C₁-C₂₀ alkyl group, a C₁-C₂₀alkoxy group, a phenyl group, a naphthyl group, an anthracenyl group,and a pyridinyl group.

In some embodiments, the compound of Formula 201 may be a compoundrepresented by Formula 201A, but is not limited thereto:

In Formula 201A, R₁₀₁, R₁₁₁, R₁₁₂, and R₁₀₉ may be the same as thosedefined above.

For example, the compound of Formula 201 and the compound of Formula 202may be Compounds HT1 to HT20 below, but are not limited thereto:

A thickness of the hole transport region may be from about 100 Å toabout 10,000 Å, and in some embodiments, from about 100 Å to about 1,000Å. When the hole transport region includes a HIL and a HTL, a thicknessof the HIL may be from about 100 Å to about 10,000 Å, and in someembodiments, from about 100 Å to about 1,000 Å, and a thickness of theHTL may be from about 50 Å to about 2,000 Å, and in some embodiments,from about 100 Å to about 1,500 Å. When the thicknesses of the holetransport region, the HIL, and the HTL are within these ranges,satisfactory hole transport characteristics may be obtained without asubstantial increase in driving voltage.

The hole transport region may further include a charge-generatingmaterial to improve conductivity, in addition to the materials asdescribed above. The charge-generating material may be homogeneously ornon-homogeneously dispersed in the hole transport region.

The charge-generating material may be, for example, a p-dopant. Thep-dopant may be one of a quinine derivative, a metal oxide, and a cyanogroup-containing compound, but is not limited thereto. Non-limitingexamples of the p-dopant are quinone derivatives such astetracyanoquinonedimethane (TCNQ),2,3,5,6-tetrafluoro-tetracyano-1,4-benzoquinonedimethane (F4-TCNQ), andthe like; metal oxides such as tungsten oxide, molybdenum oxide, and thelike; and cyano-containing compounds such as Compound 200 below.

The hole transport region may further include a buffer layer.

The buffer layer may compensate for an optical resonance distance oflight according to a wavelength of the light emitted from the EML, andthus may increase efficiency.

The EML may be formed on the hole transport region by using vacuumdeposition, spin coating, casting, LB deposition, or the like. When theEML is formed using vacuum deposition or spin coating, the conditionsfor deposition and coating may be similar to those for the formation ofthe HIL, though the conditions for the deposition and coating may varydepending on the material that is used to form the EML.

The EML may include a host and a dopant.

The host may include at least one of TPBi, TBADN, AND (also referred toas “DNA”), CBP, CDBP, and TCP:

In some embodiments, the host may further include a compound representedby Formula 301:

In Formula 301, Ar₁₁₁ and Ar₁₁₂ may be each independently

a phenylene group, a naphthylene group, a phenanthrenylene group, or apyrenylene group, or

a phenylene group, a naphthylene group, a phenanthrenylene group, afluorenyl group, or a pyrenylene group, each substituted with at leastone of a phenyl group, a naphthyl group, and an anthracenyl group.

In Formula 301, Ar₁₁₃ to Ar₁₁₆ may be each independently

a C₁-C₁₀ alkyl group, a phenyl group, a naphthyl group, a phenanthrenylgroup, or a pyrenyl group, or

a phenyl group, a naphthyl group, a phenanthrenyl group, a fluorenylgroup, or a pyrenyl group, each substituted with at least one of aphenyl group, a naphthyl group, and an anthracenyl group.

In Formula 301, g, h, l, and j may be each independently an integer of 0to 4, for example, 0, 1, or 2.

In Formula 301, Ar₁₁₃ to Ar₁₁₆ may be each independently

a C₁-C₁₀ alkyl group substituted with at least one of a phenyl group, anaphthyl group, and an anthracenyl group,

a phenyl group, a naphthyl group, an anthracenyl group, a pyrenyl group,a phenanthrenyl group, or a fluorenyl group,

a phenyl group, a naphthyl group, an anthracenyl group, a pyrenyl group,a phenanthrenyl group, or a fluorenyl group, each substituted with atleast one of a deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyanogroup, a nitro group, an amino group, an amidino group, a hydrazinegroup, a hydrazone group, a carboxylic acid group or a salt thereof, asulfonic acid group or a salt thereof, a phosphoric acid group or a saltthereof, a C₁-C₆₀ alkyl group, a C₂-C₆₀ alkenyl group, a C₂-C₆₀ alkynylgroup, a C₁-C₆₀ alkoxy group, a phenyl group, a naphthyl group, ananthracenyl group, a pyrenyl group, a phenanthrenyl group, and afluorenyl group, or

However, embodiments of the present inventive concept are not limitedthereto.

In some embodiments, the host may include a compound represented byFormula 302:

In Formula 302, Ar₁₂₂ to Ar₁₂₅ may be defined the same as for Ar₁₁₃ inFormula 301 described above.

In Formula 302, Ar₁₂₆ and Ar₁₂₇ may be each independently a C₁-C₁₀ alkylgroup, for example, a methyl group, an ethyl group, or a propyl group.

In Formula 302, k and l may be each independently an integer of 0 to 4,for example, 0, 1, or 2.

Non-limiting examples of the compound of Formula 301 and the compound ofFormula 302 may include Compounds H1 to H42. However, embodiments of thepresent inventive concept are not limited thereto.

When the organic light-emitting device is a full color organiclight-emitting device, the emission layer may be patterned into a redemission layer, a green emission layer, and a blue emission layer. Insome embodiments, the EML may have a stack structure including a redemission layer, a green emission layer, and/or a blue emission layerthat are stacked upon one another to emit white light, but is notlimited thereto.

The EML may include the organometallic compound of Formula 1 as adopant.

When the EML includes both a host and a dopant, the amount of the dopantmay be from about 0.01 to about 20 parts by weight based on 100 parts byweight of the host. However, the amount of the dopant is not limited tothis range.

The thickness of the EML may be about 100 Å to about 1,000 Å, and insome embodiments, may be from about 200 Å to about 600 Å. When thethickness of the EML is within these ranges, the EML may have improvedlight emitting ability without a substantial increase in drivingvoltage.

Next, the electron transport region may be formed on the EML.

The electron transport region may include at least one of a HBL, an ETL,and an EIL.

In some embodiments, the electron transport region may have a structureincluding a HBL/ETL/EIL, or an ETL/EIL, wherein the layers forming thestructure of the electron transport region may be sequentially stackedon the EML in the stated order. However, embodiments of the presentdisclosure are not limited thereto. The ETL may have a single-layerstructure or a multi-layer structure including at least two differentmaterials.

Conditions for forming the HBL, ETL, and EIL of the electron transportregion may be the same as those for the HIL described above.

When the electron transport region includes the HBL, the HBL may includeat least one of BCP below and Bphen below. However, embodiments of thepresent disclosure are not limited thereto.

The thickness of the HBL may be from about 20 Å to about 1,000 Å, and insome embodiments, from about 30 Å to about 300 Å. When the thickness ofthe HBL is within these ranges, the HBL may have improved hole blockingability without a substantial increase in driving voltage.

The ETL may further include at least one of Alq₃, Balq, TAZ, and NTAZ,in addition to BCP and Bphen described above.

In some embodiments, the ETL may include at least one of Compounds ET1and ET2 represented below, but is not limited thereto.

A thickness of the ETL may be from about 100 Å to about 1,000 Å, and insome embodiments, from about 150 Å to about 500 Å. When the thickness ofthe ETL is within these ranges, the ETL may have satisfactory electrontransporting ability without a substantial increase in driving voltage.

In some embodiments the ETL may further include a metal-containingmaterial, in addition to the above-described materials.

The metal-containing material may include a lithium (Li) complex.Non-limiting examples of the Li complex are compound ET-D1 below(lithium quinolate (LiQ)), or compound ET-D2 below.

The electron transport region may include an EIL that may facilitateinjection of electrons from the second electrode 19. The EIL may includeat least one selected from LiF, NaCl, CsF, Li₂O, and BaO. The thicknessof the EIL may be from about 1 Å to about 100 Å, and in someembodiments, from about 3 Å to about 90 Å. When the thickness of the EILis within these ranges, the EIL may have satisfactory electron injectionability without a substantial increase in driving voltage.

The second electrode 19 is disposed on the organic layer 15. The secondelectrode 19 may be a cathode. A material for the second electrode 19may be a metal, an alloy, or an electrically conductive compound thathave a low work function, or a combination thereof. Non-limitingexamples of the material for the second electrode 19 are lithium (Li),magnesium (Mg), aluminum (Al), aluminum (Al)-lithium (Li), calcium (Ca),magnesium (Mg)-indium (In), and magnesium (Mg)-silver (Ag), or the like.In some embodiments, to manufacture a top-emission light-emittingdevice, the second electrode 19 may be formed as a transmissiveelectrode from, for example, indium tin oxide (ITO) or indium zinc oxide(IZO).

Although the organic light-emitting device of FIG. 1 is described above,embodiments of the present disclosure are not limited thereto.

As used herein, a C₁-C₆₀ alkyl group refers to a linear or branchedaliphatic hydrocarbon monovalent group having 1 to 60 carbon atoms.Non-limiting examples of the C₁-C₆₀ alkyl group a methyl group, an ethylgroup, a propyl group, an isobutyl group, a sec-butyl group, atert-butyl group, a pentyl group, an iso-amyl group, and a hexyl group.A C₁-C₆₀ alkylene group refers to a divalent group having the samestructure as the C₁-C₆₀ alkyl.

As used herein, a C₁-C₆₀ alkoxy group refers to a monovalent grouprepresented by —OA₁₀₁ (where A₁₀₁ is a C₁-C₆₀ alkyl group as describedabove. Non-limiting examples of the C₁-C₆₀ alkoxy group are a methoxygroup, an ethoxy group, and an isopropyloxy group.

As used herein, a C₂-C₆₀ alkenyl group refers to a structure includingat least one carbon double bond in the middle or at the terminal of theC₂-C₆₀ alkyl group. Non-limiting examples of the C₂-C₆₀ alkenyl groupare an ethenyl group, a propenyl group, and a butenyl group. A C₂-C₆₀alkylene group refers to a divalent group having the same structure asthe C₂-C₆₀ alkenyl group.

As used herein, a C₂-C₆₀ alkynyl group refers to a structure includingat least one carbon triple bond in the middle or at the terminal of theC₂-C₆₀ alkyl group. Non-limiting examples of the C₂-C₆₀ alkynyl groupare an ethynyl group and a propynyl group. A C₂-C₆₀ alkynylene groupused herein refers to a divalent group having the same structure as theC₂-C₆₀ alkynyl group.

As used herein, a C₃-C₁₀ cycloalkyl group refers to a monovalent,monocyclic hydrocarbon group having 3 to 10 carbon atoms. Non-limitingexamples of the C₃-C₁₀ cycloalkyl group are a cyclopropyl group, acyclobutyl group, a cyclopentyl group, a cyclohexyl group, and acycloheptyl group. A C₃-C₁₀ cycloalkylene group refers to a divalentgroup having the same structure as the C₃-C₁₀ cycloalkyl group.

As used herein, a C₂-C₁₀ heterocycloalkyl group refers to a monovalentmonocyclic group having 2 to 10 carbon atoms in which at least onehetero atom selected from N, O, P, and S is included as a ring-formingatom. Non-limiting examples of the C₃-C₁₀ heterocycloalkyl group are atetrahydrofuranyl group and a tetrahydrothiophenyl group. A C₂-C₁₀heterocycloalkylene group refers to a divalent group having the samestructure as the C₂-C₁₀ heterocycloalkyl group.

As used herein, a C₃-C₁₀ cycloalkenyl group refers to a monovalentmonocyclic group having 3 to 10 carbon atoms that includes at least onedouble bond in the ring but does not have aromaticity. Non-limitingexamples of the C₃-C₁₀ cycloalkenyl group are a cyclopentenyl group, acyclohexenyl group, and a cycloheptenyl group. A C₃-C₁₀ cycloalkenylenegroup refers to a divalent group having the same structure as the C₃-C₁₀cycloalkenyl group.

As used herein, a C₂-C₁₀ heterocycloalkenyl group used herein refers toa monovalent monocyclic group having 2 to 10 carbon atoms that includesat least one double bond in the ring and in which at least one heteroatom selected from N, O, P, and S is included as a ring-forming atom.Non-limiting examples of the C₂-C₁₀ heterocycloalkenyl group are a2,3-dihydrofuranyl group and a 2,3-dihydrothiophenyl group. A C₂-C₁₀heterocycloalkenylene group used herein refers to a divalent grouphaving the same structure as the C₂-C₁₀ heterocycloalkenyl group.

As used herein, a C₆-C₆₀ aryl group refers to a monovalent, aromaticcarbocyclic aromatic group having 6 to 60 carbon atoms, and a C₆-C₆₀arylene group refers to a divalent, aromatic carbocyclic group having 6to 60 carbon atoms. Non-limiting examples of the C₆-C₆₀ aryl group are aphenyl group, a naphthyl group, an anthracenyl group, a phenanthrenylgroup, a pyrenyl group, and a chrysenyl group. When the C₆-C₆₀ arylgroup and the C₆-C₆₀ arylene group include at least two rings, the ringsmay be fused to each other.

As used herein, a C₂-C₆₀ heteroaryl group refers to a monovalent,aromatic carbocyclic aromatic group having 2 to 60 carbon atoms in whichat least one heteroatom selected from N, O, P, and S is included as aring-forming atom, and 2 to 60 carbon atoms. A C₂-C₆₀ heteroarylenegroup refers to a divalent, aromatic carbocyclic group having 2 to 60carbon atoms in which at least one hetero atom selected from N, O, P,and S is included as a ring-forming atom. Non-limiting examples of theC₂-C₆₀ heteroaryl group are a pyridinyl group, a pyrimidinyl group, apyrazinyl group, a pyridazinyl group, a triazinyl group, a quinolinylgroup, and an isoquinolinyl group. When the C₂-C₆₀ heteroaryl and theC₂-C₆₀ heteroarylene include at least two rings, the rings may be fusedto each other.

As used herein, a C₆-C₆₀ aryloxy group indicates —OA₁₀₂ (where A₁₀₂ is aC₆-C₆₀ aryl group as described above), and a C₆-C₆₀ arylthio groupindicates —SA₁₀₃ (where A₁₀₃ is a C₆-C₆₀ aryl group as described above).

As used herein, a monovalent non-aromatic condensed polycyclic grouprefers to a monovalent group having at least two rings condensed to eachother, in which only carbon atoms (for example, 8 to 60 carbon atoms)are exclusively included as ring-forming atoms and the entire moleculeis non-aromatic. A non-limiting example of the monovalent non-aromaticcondensed polycyclic group is a fluorenyl group. A divalent non-aromaticcondensed polycyclic group refers to a divalent group having the samestructure as the monovalent non-aromatic condensed polycyclic group.

As used herein, a monovalent non-aromatic condensed heteropolycyclicgroup refers to a monovalent group having at least two rings condensedto each other, in which carbon atoms (for example, 2 to 60 carbon atoms)and a hetero atom selected from N, O, P, and S are as ring-forming atomsand the entire molecule is non-aromatic. A non-limiting example of themonovalent non-aromatic condensed heteropolycyclic group is a carbazolylgroup. A divalent non-aromatic condensed heteropolycyclic group refersto a divalent group having the same structure as the monovalentnon-aromatic condensed heteropolycyclic group.

As used herein, at least one substituent of the substituted C₁-C₆₀ alkylgroup, the substituted C₂-C₆₀ alkenyl group, the substituted C₂-C₆₀alkynyl group, the substituted C₁-C₆₀ alkoxy group, the substitutedC₃-C₁₀ cycloalkyl group, the substituted C₂-C₁₀ heterocycloalkyl group,the substituted C₃-C₁₀ cycloalkenyl group, the substituted C₂-C₁₀heterocycloalkenyl group, the substituted C₆-C₆₀ aryl group, thesubstituted C₆-C₆₀ aryloxy group, the substituted C₆-C₆₀ arylthio group,the substituted C₂-C₆₀ heteroaryl group, the substituted monovalentnon-aromatic condensed polycyclic group, and the substituted monovalentnon-aromatic condensed heteropolycyclic group may be selected from

a deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitrogroup, an amino group, an amidino group, a hydrazine group, a hydrazonegroup, a carboxylic acid group or a salt thereof, a sulfonic acid groupor a salt thereof, a phosphoric acid group or a salt thereof, a C₁-C₆₀alkyl group, a C₂-C₆₀ alkenyl group, a C₂-C₆₀ alkynyl group, and C₁-C₆₀alkoxy group;

a C₁-C₆₀ alkyl group, a C₂-C₆₀ alkenyl group, a C₂-C₆₀ alkynyl group,and C₁-C₆₀ alkoxy group, each substituted with at least one of adeuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitrogroup, an amino group, an amidino group, a hydrazine group, a hydrazonegroup, a carboxylic acid group or a salt thereof, a sulfonic acid groupor a salt thereof, a phosphoric acid group or a salt thereof, a C₃-C₁₀cycloalkyl group, a C₂-C₁₀ heterocycloalkyl group, a C₃-C₁₀ cycloalkenylgroup, a C₂-C₁₀ heterocycloalkenyl group, a C₆-C₆₀ aryl group, a C₆-C₆₀aryloxy group, a C₆-C₆₀ arylthio group, a C₂-C₆₀ heteroaryl group, amonovalent non-aromatic condensed polycyclic group, a monovalentnon-aromatic condensed heteropolycyclic group, —N(Q₁₁)(Q₁₂),—Si(Q₁₃)(Q₁₄)(Q₁₅), and —B(Q₁₆)(Q₁₇),

a C₃-C₁₀ cycloalkyl group, a C₂-C₁₀ heterocycloalkyl group, a C₃-C₁₀cycloalkenyl group, a C₂-C₁₀ heterocycloalkenyl group, a C₆-C₆₀ arylgroup, a C₆-C₆₀ aryloxy group, a C₆-C₆₀ arylthio group, a C₂-C₆₀heteroaryl group, a monovalent non-aromatic condensed polycyclic group,and a monovalent non-aromatic condensed heteropolycyclic group,

a C₃-C₁₀ cycloalkyl group, a C₂-C₁₀ heterocycloalkyl group, a C₃-C₁₀cycloalkenyl group, a C₂-C₁₀ heterocycloalkenyl group, a C₆-C₆₀ arylgroup, a C₆-C₆₀ aryloxy group, a C₆-C₆₀ arylthio group, a C₂-C₆₀heteroaryl group, a monovalent non-aromatic condensed polycyclic group,and a monovalent non-aromatic condensed heteropolycyclic group, eachsubstituted with at least one of a deuterium, —F, —Cl, —Br, —I, ahydroxyl group, a cyano group, a nitro group, an amino group, an amidinogroup, a hydrazine group, a hydrazone group, a carboxylic acid group ora salt thereof, a sulfonic acid group or a salt thereof, a phosphoricacid group or a salt thereof, a C₁-C₆₀ alkyl group, a C₂-C₆₀ alkenylgroup, a C₂-C₆₀ alkynyl group, a C₁-C₆₀ alkoxy group, a C₃-C₁₀cycloalkyl group, a C₂-C₁₀ heterocycloalkyl group, a C₃-C₁₀ cycloalkenylgroup, a C₂-C₁₀ heterocycloalkenyl group, a C₆-C₆₀ aryl group, a C₆-C₆₀aryloxy group, a C₆-C₆₀ arylthio group, a C₂-C₁₀ heteroaryl group, amonovalent non-aromatic condensed polycyclic group, a monovalentnon-aromatic condensed heteropolycyclic group, —N(Q₂₁)(Q₂₂),—Si(Q₂₃)(Q₂₄)(Q₂₅), and —B(Q₂₆)(Q₂₇), and

—N(Q₃₁)(Q₃₂), —Si(Q₃₃)(Q₃₄)(Q₃₅), and —B(Q₃₆)(Q₃₇),

wherein Q₁ to Q₃, Q₁₁ to Q₁₇, Q₂₁ to Q₂₇, and Q₃₁ to Q₃₇ may be eachindependently selected from a hydrogen, a deuterium, —F, —Cl, —Br, —I, ahydroxyl group, a cyano group, a nitro group, an amino group, an amidinogroup, a hydrazine group, a hydrazone group, a carboxylic acid group ora salt thereof, a sulfonic acid group or a salt thereof, a phosphoricacid group or a salt thereof, a C₁-C₆₀ alkyl group, a C₂-C₆₀ alkenylgroup, a C₂-C₆₀ alkynyl group, a C₁-C₆₀ alkoxy group, a C₃-C₁₀cycloalkyl group, a C₂-C₁₀ heterocycloalkyl group, a C₃-C₁₀ cycloalkenylgroup, a C₂-C₁₀ heterocycloalkenyl group, a C₆-C₆₀ aryl group, a C₆-C₆₀aryloxy group, a C₆-C₆₀ arylthio group, a C₂-C₆₀ heteroaryl group, amonovalent non-aromatic condensed polycyclic group, and a monovalentnon-aromatic condensed heteropolycyclic group.

In some embodiments, as used herein, at least one substituent of thesubstituted C₁-C₆₀ alkyl group, the substituted C₂-C₆₀ alkenyl group,the substituted C₂-C₆₀ alkynyl group, the substituted C₁-C₆₀ alkoxygroup, the substituted C₃-C₁₀ cycloalkyl group, the substituted C₂-C₁₀heterocycloalkyl group, the substituted C₃-C₁₀ cycloalkenyl group, thesubstituted C₂-C₁₀ heterocycloalkenyl group, the substituted C₆-C₆₀ arylgroup, the substituted C₆-C₆₀ aryloxy group, the substituted C₆-C₆₀arylthio group, the substituted C₂-C₆₀ heteroaryl group, the substitutedmonovalent non-aromatic condensed polycyclic group, and the substitutedmonovalent non-aromatic condensed heteropolycyclic group may be selectedfrom

a deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitrogroup, an amino group, an amidino group, a hydrazine group, a hydrazonegroup, a carboxylic acid group or a salt thereof, a sulfonic acid groupor a salt thereof, a phosphoric acid group or a salt thereof, a C₁-C₆₀alkyl group, a C₂-C₆₀ alkenyl group, a C₂-C₆₀ alkynyl group, and C₁-C₆₀alkoxy group,

a C₁-C₆₀ alkyl group, a C₂-C₆₀ alkenyl group, a C₂-C₆₀ alkynyl group,and a C₁-C₆₀ alkoxy group, each substituted with at least one of adeuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitrogroup, an amino group, an amidino group, a hydrazine group, a hydrazonegroup, a carboxylic acid group or a salt thereof, a sulfonic acid groupor a salt thereof, a phosphoric acid group or a salt thereof, acyclopentyl group, a cyclohexyl group, a cycloheptyl group, acyclopentenyl group, a cycloheptenyl group, a phenyl group, a pentalenylgroup, an indenyl group, a naphthyl group, an azulenyl group, aheptalenyl group, an indacenyl group, an acenaphthyl group, a fluorenylgroup, a spiro-fluorenyl group, a benzofluorenyl group, adibenzofluorenyl group, a phenalenyl group, a phenanthrenyl group, ananthracenyl group, a fluoranthenyl group, a triphenylenyl group, apyrenyl group, a chrysenyl group, a naphthacenyl group, a picenyl group,a perylenyl group, a pentaphenyl group, a hexacenyl group, a pentacenylgroup, a rubicenyl group, a coronenyl group, an ovalenyl group, apyrrolyl group, a thiophenyl group, a furanyl group, an imidazolylgroup, a pyrazolyl group, a thiazolyl group, an isothiazolyl group, anoxazolyl group, an isoxazolyl group, a pyridinyl group, a pyrazinylgroup, a pyrimidinyl group, a pyridazinyl group, an isoindolyl group, anindolyl group, an indazolyl group, a purinyl group, a quinolinyl group,an isoquinolinyl group, a benzoquinolinyl group, a phthalazinyl group, anaphthyridinyl group, a quinoxalinyl group, a quinazolinyl group, acinnolinyl group, a carbazolyl group, a phenanthridinyl group, anacridinyl group, a phenanthrolinyl group, a phenazinyl group, abenzoimidazolyl group, a benzofuranyl group, a benzothiophenyl group, anisobenzothiazolyl group, a benzoxazolyl group, an isobenzoxazolyl group,a triazolyl group, a tetrazolyl group, an oxadiazolyl group, a triazinylgroup, a dibenzofuranyl group, a dibenzothiophenyl group, abenzocarbazolyl group, a dibenzocarbazolyl group, an imidazopyridinylgroup, an imidazopyrimidinyl group, N(Q₁₁)(Q₁₂), —Si(Q₁₃)(Q₁₄)(Q₁₅), and—B(Q₁₆)(Q₁₇),

a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, acyclopentenyl group, a cycloheptenyl group, a phenyl group, a pentalenylgroup, an indenyl group, a naphthyl group, an azulenyl group, aheptalenyl group, an indacenyl group, an acenaphthyl group, a fluorenylgroup, a spiro-fluorenyl group, a benzofluorenyl group, adibenzofluorenyl group, a phenalenyl group, a phenanthrenyl group, ananthracenyl group, a fluoranthenyl group, a triphenylenyl group, apyrenyl group, a chrysenyl group, a naphthacenyl group, a picenyl group,a perylenyl group, a pentaphenyl group, a hexacenyl group, a pentacenylgroup, a rubicenyl group, a coronenyl group, an ovalenyl group, apyrrolyl group, a thiophenyl group, a furanyl group, an imidazolylgroup, a pyrazolyl group, a thiazolyl group, an isothiazolyl group, anoxazolyl group, an isoxazolyl group, a pyridinyl group, a pyrazinylgroup, a pyrimidinyl group, a pyridazinyl group, an isoindolyl group, anindolyl group, an indazolyl group, a purinyl group, a quinolinyl group,an isoquinolinyl group, a benzoquinolinyl group, a phthalazinyl group, anaphthyridinyl group, a quinoxalinyl group, a quinazolinyl group, acinnolinyl group, a carbazolyl group, a phenanthridinyl group, anacridinyl group, a phenanthrolinyl group, a phenazinyl group, abenzoimidazolyl group, a benzofuranyl group, a benzothiophenyl group, anisobenzothiazolyl group, a benzoxazolyl group, an isobenzoxazolyl group,a triazolyl group, a tetrazolyl group, an oxadiazolyl group, a triazinylgroup, a dibenzofuranyl group, a dibenzothiophenyl group, abenzocarbazolyl group, a dibenzocarbazolyl group, an imidazopyridinylgroup, and an imidazopyrimidinyl group,

a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, acyclopentenyl group, a cycloheptenyl group, a phenyl group, a pentalenylgroup, an indenyl group, a naphthyl group, an azulenyl group, aheptalenyl group, an indacenyl group, an acenaphthyl group, a fluorenylgroup, a spiro-fluorenyl group, a benzofluorenyl group, adibenzofluorenyl group, a phenalenyl group, a phenanthrenyl group, ananthracenyl group, a fluoranthenyl group, a triphenylenyl group, apyrenyl group, a chrysenyl group, a naphthacenyl group, a picenyl group,a perylenyl group, a pentaphenyl group, a hexacenyl group, a pentacenylgroup, a rubicenyl group, a coronenyl group, an ovalenyl group, apyrrolyl group, a thiophenyl group, a furanyl group, an imidazolylgroup, a pyrazolyl group, a thiazolyl group, an isothiazolyl group, anoxazolyl group, an isoxazolyl group, a pyridinyl group, a pyrazinylgroup, a pyrimidinyl group, a pyridazinyl group, an isoindolyl group, anindolyl group, an indazolyl group, a purinyl group, a quinolinyl group,an isoquinolinyl group, a benzoquinolinyl group, a phthalazinyl group, anaphthyridinyl group, a quinoxalinyl group, a quinazolinyl group, acinnolinyl group, a carbazolyl group, a phenanthridinyl group, anacridinyl group, a phenanthrolinyl group, a phenazinyl group, abenzoimidazolyl group, a benzofuranyl group, a benzothiophenyl group, anisobenzothiazolyl group, a benzoxazolyl group, an isobenzoxazolyl group,a triazolyl group, a tetrazolyl group, an oxadiazolyl group, a triazinylgroup, a dibenzofuranyl group, a dibenzothiophenyl group, abenzocarbazolyl group, a dibenzocarbazolyl group, an imidazopyridinylgroup, and an imidazopyrimidinyl group, each substituted with at leastone of a deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, anitro group, an amino group, an amidino group, a hydrazine group, ahydrazone group, a carboxylic acid group or a salt thereof, a sulfonicacid group or a salt thereof, a phosphoric acid group or a salt thereof,a C₁-C₆₀ alkyl group, a C₂-C₆₀ alkenyl group, a C₂-C₆₀ alkynyl group, aC₁-C₆₀ alkoxy group, a phenyl group, a naphthyl group, —N(Q₂₁)(Q₂₂),—Si(Q₂₃)(Q₂₄)(Q₂₅), and —B(Q₂₆)(Q₂₇), and

—N(Q₃₁)(Q₃₂), —Si(Q₃₃)(Q₃₄)(Q₃₅), and —B(Q₃₆)(Q₃₇),

wherein Q₁ to Q₃, Q₁₁ to Q₁₇, Q₂₁ to Q₂₇, and Q₃₁ to Q₃₇ may be eachindependently selected from a hydrogen, a deuterium, —F, —Cl, —Br, —I, ahydroxyl group, a cyano group, a nitro group, an amino group, an amidinogroup, a hydrazine group, a hydrazone group, a carboxylic acid group ora salt thereof, a sulfonic acid group or a salt thereof, a phosphoricacid group or a salt thereof, a C₁-C₆₀ alkyl group, a C₂-C₆₀ alkenylgroup, a C₂-C₆₀ alkynyl group, a C₁-C₆₀ alkoxy group, a cyclopentylgroup, a cyclohexyl group, a cycloheptyl group, a cyclopentenyl group, acycloheptenyl group, a phenyl group, a pentalenyl group, an indenylgroup, a naphthyl group, an azulenyl group, a heptalenyl group, anindacenyl group, an acenaphthyl group, a fluorenyl group, aspiro-fluorenyl group, a benzofluorenyl group, a dibenzofluorenyl group,a phenalenyl group, a phenanthrenyl group, an anthracenyl group, afluoranthenyl group, a triphenylenyl group, a pyrenyl group, a chrysenylgroup, a naphthacenyl group, a picenyl group, a perylenyl group, apentaphenyl group, a hexacenyl group, a pentacenyl group, a rubicenylgroup, a coronenyl group, an ovalenyl group, a pyrrolyl group, athiophenyl group, a furanyl group, an imidazolyl group, a pyrazolylgroup, a thiazolyl group, an isothiazolyl group, an oxazolyl group, anisoxazolyl group, a pyridinyl group, a pyrazinyl group, a pyrimidinylgroup, a pyridazinyl group, an isoindolyl group, an indolyl group, anindazolyl group, a purinyl group, a quinolinyl group, an isoquinolinylgroup, a benzoquinolinyl group, a phthalazinyl group, a naphthyridinylgroup, a quinoxalinyl group, a quinazolinyl group, a cinnolinyl group, acarbazolyl group, a phenanthridinyl group, an acridinyl group, aphenanthrolinyl group, a phenazinyl group, a benzoimidazolyl group, abenzofuranyl group, a benzothiophenyl group, an isobenzothiazolyl group,a benzoxazolyl group, an isobenzoxazolyl group, a triazolyl group, atetrazolyl group, an oxadiazolyl group, a triazinyl group, adibenzofuranyl group, a dibenzothiophenyl group, a benzocarbazolylgroup, a dibenzocarbazolyl group, an imidazopyridinyl group, and animidazopyrimidinyl group.

Hereinafter, the present inventive concept will be described in detailwith reference to the following synthesis examples and other examples ofcompounds and organic light-emitting devices. However, these examplesare for illustrative purposes only and are not intended to limit thescope of the present inventive concept. In the following synthesisexamples, the expression that “‘B’ instead of ‘A’ was used” means thatthe amounts of ‘B’ and ‘A’ were the same in equivalent amounts.

EXAMPLES Synthesis Example 1: Synthesis of Compound 52

A solution of n-BuLi in hexane (2.77 M, 0.14 mL, 0.4 mmol) was added toa solution of 3-trifluoromethyl pyrazole (0.4 mmol) in tetrahydrofuran(THF, 5 mL) in a 100-mL Schlenk flask at room temperature in an argonatmosphere. The resulting reaction product was stirred at roomtemperature for about 2 hours, and 50 mg (0.4 mmol) ofdiisopropylcarbodiimide was dropwise added thereto and stirred for about2 hours. Then, a solution of Intermediate A (0.2 mmol) in THF (15 mL)was dropwise added thereto and stirred at about 80C for about 16 hours.The resulting reaction product was cooled down to room temperature, andthen the solvent was removed under reduced pressure. The residue wasdissolved in toluene, and the toluene was removed under reducedpressure, thereby completely removing THF from the residue. Theresulting reaction product was dissolved again in toluene, filtered toremove lithium chloride, and washed with Et₂O to obtain Compound 52 (240mg, Yield: 72%).

¹H NMR: 300 MHz, CDCl₃, rt: δ 8.30 (d, J=8.5 Hz, 2H,), 7.81 (m, 4H),7.18 (t, 2H), 6.73 (s, 1H), 6.4 (s, 1H), 3.65-3.82 (m, 2H), 1.28 (d,6H), 0.91 (d, 6H).

MS (MALDI-TOF) [m/e]: 828.20

Synthesis Example 2: Synthesis of Compound 19

Compound 19 (303 mg, Yield: 76%) was synthesized in the same manner asin Synthesis Example 1, except that Intermediate B instead ofIntermediate A was used.

MS (MALDI-TOF) [m/e]: 998.2

Synthesis Example 3: Synthesis of Compound 2

Compound 2 (292 mg, Yield: 81%) was synthesized in the same manner as inSynthesis Example 1, except that 3,5-bis(trifluoromethyl)-pyrazoleinstead of 3-trifluoromethyl-pyrazole was used.

MS (MALDI-TOF) [m/e]: 904.1

Synthesis Example 4: Synthesis of Compound 50

Compound 50 (290 mg, Yield: 78%) was synthesized in the same manner asin Synthesis Example 1, except that pyrazole and Intermediate B insteadof 3-trifluoromethyl pyrazole and Intermediate A, respectively, wereused.

MS (MALDI-TOF) [m/e]: 930.0

Synthesis Example 5: Synthesis of Compound 1

Compound 1 (209 mg, Yield: 68%) was synthesized in the same manner as inSynthesis Example 1, except that pyrazole instead of 3-trifluoromethylpyrazole was used.

MS (MALDI-TOF) [m/e]: 768.20

Synthesis Example 6: Synthesis of Compound 3

Compound 3 (268 mg, Yield: 82%) was synthesized in the same manner as inSynthesis Example 1, except that 4,5-dicyano-imidazole instead of3-trifluoromethyl-pyrazole was used.

MS (MALDI-TOF) [m/e]: 818.10

Synthesis Example 7: Synthesis of Compound 5

Compound 5 (200 mg, Yield: 65%) was synthesized in the same manner as inSynthesis Example 1, except that 1,2,4-triazole instead of3-trifluoromethyl-pyrazole was used.

MS (MALDI-TOF) [m/e]: 769.2

Synthesis Example 8: Synthesis of Compound 9

Compound 9 (298 mg, Yield: 80%) was synthesized in the same manner as inSynthesis Example 1, except that 1,2,4-triazole and Intermediate Binstead of 3-trifluoromethyl-pyrazole and Intermediate A, respectively,were used.

MS (MALDI-TOF) [m/e]: 769.2

Synthesis Example 9: Synthesis of Compound 54

Compound 54 (223 mg, Yield: 62%) was synthesized in the same manner asin Synthesis Example 1, except that 5-methyl-tetrazole and IntermediateD instead of 3-trifluoromethyl-pyrazole and Intermediate A,respectively, were used.

MS (MALDI-TOF) [m/e]: 896.12

Synthesis Example 10: Synthesis of Compound 53

Compound 53 (220 mg, Yield: 58%) was synthesized in the same manner asin Synthesis Example 1, except that Intermediate D instead ofIntermediate A was used.

¹H NMR: 300 MHz, CDCl₃, rt: δ 8.32 (d, J=8.45 Hz, 2H), 7.91 (m, 1H),7.83 (d, 1H), 7.21 (d, 2H), 6.75 (s, 2H), 6.49 (s, 1H), 5.7 (s, 1H),3.54-3.83 (m, 2H), 1.56 (d, 6H), 1.46 (s, 9H), 0.02 (d, 6H).

MS (MALDI-TOF) [m/e]: 948.34

Synthesis Example 11: Synthesis of Compound 51

Compound 51 (223 mg, Yield: 63%) was synthesized in the same manner asin Synthesis Example 1, except that Intermediate E instead ofIntermediate A was used.

MS (MALDI-TOF) [m/e]: 884.20

Synthesis Example 12: Synthesis of Compound 56

Compound 56 (251 mg, Yield: 72%) was synthesized in the same manner asin Synthesis Example 1, except that Intermediate F instead ofIntermediate A was used.

¹H NMR: 300 MHz, CDCl₃, rt: δ 8.99 (d, J=8.35 Hz, 2H), 7.97 (d, 2H),6.79-6.94 (m, 4H), 6.70 (m, 2H), 6.55 (s, 1H), 6.07 (s, 1H), 4.25 (s,3H), 3.31-3.36 (m, 2H), 2.07 (d, 6H), 1.16 (d, 6H).

MS (MALDI-TOF) [m/e]: 904.0

Synthesis Example 13: Synthesis of Compound 30

Compound 30 (194 mg, Yield: 52%) was synthesized in the same manner asin Synthesis Example 1, except that sodium dicyanoimide and IntermediateB instead of 3-trifluoromethyl-pyrazole and Intermediate A,respectively, were used.

MS (MALDI-TOF) [m/e]: 929.10

Evaluation Example 1: Evaluation of Photoluminescence (PL) Spectrum andPhotoluminescence Quantum Yield (PLQY)

Compound 52 was diluted in toluene to a concentration of 10 mM, and thephotoluminescence (PL) of Compound 52 in the solution was measured usingan ISC PC1 Spectrofluorometer equipped with a Xenon lamp. The samemeasurement was repeated for Compounds 19, 2, 50, 1, 3, 5, 9, 54, 53,51, 56, and 30. PL spectra of Compounds 52, 19, 2, 50, 1, 3, 5, 9, 54,53, 51, 56, and 30 are shown in FIGS. 2 to 14, respectively.

A solution of polymethylmethacrylate (PMMA) in CH₂Cl₂ was mixed with 8weight % of Compound 52 to obtain a mixture. This mixture was coated ona quartz substrate by using a spin coater, thermally treated in a 80° C.oven, and cooled down to room temperature to form a film. This film wasused to evaluate photoluminescence quantum yield (PLQY) and colorcoordination of compound 52. The photoluminescence quantum yield in filmand the color coordination in film of Compound 52 were evaluated using aHamamatsu Photonics absolute PL quantum yield measurement system usingPLQY measurement software (Hamamatsu Photonics, Ltd., Shizuoka, Japan),equipped with a Xenon light source, a monochromator, a photonicmultichannel analyzer, and an integrating sphere. The same evaluation asabove was repeated for Compounds 19, 2, 50, 1, 3, 5, 9, 54, 53, 51, 56,and 30 and Compounds A to D to obtain photoluminescence quantum yieldsand color purity data thereof, which are shown in Table 1.

TABLE 1 Compound No. PLQY (%) CIE_X CIE_Y 52 73 0.16 0.26 19 65 0.170.32  2 66 0.18 0.34 50 58 0.17 0.34  1 68 0.19 0.36  3 48 0.23 0.40  556 0.18 0.33  9 54 0.17 0.35 54 64 0.17 0.30 53 78 0.16 0.26 51 75 0.160.30 56 86 0.22 0.41 30 68 0.16 0.27 A 22 0.38 0.58 B 36 0.42 0.56 C 180.43 0.55 D 16 0.46 0.52

Referring to FIGS. 2 to 14 and Table 1, Compounds 52, 19, 2, 50, 1, 3,5, 9, 54, 53, 51, 56, and 30 were found to have higher photoluminescencequantum yields compared to those of Compounds A, B, C, and D, and emithigh-purity blue light.

As described above, according to the one or more of the aboveembodiments of the present inventive concept, an organometallic compoundrepresented by Formula 1 may have improved electric characteristics andimproved thermal stability, and thus an organic light-emitting deviceincluding the organometallic compound may have a low driving voltage, ahigh efficiency, a high luminance, and improved lifetimecharacteristics.

It should be understood that the exemplary embodiments described thereinshould be considered in a descriptive sense only and not for purposes oflimitation. Descriptions of features or aspects within each embodimentshould typically be considered as available for other similar featuresor aspects in other embodiments.

What is claimed is:
 1. An organometallic compound represented by Formula1:M(L₁)_(n1)(L₂)_(n2)  Formula 1 wherein, in Formula 1, L₁ is a ligandrepresented by Formula 2, and L₂ is a ligand represented by one ofFormulae 3 to 5:

wherein, in Formulae 1 to 5, M is Ir, Pt, Os, Ti, Zr, Hf, Eu, Tb, or Tm;CY₁ and CY₂ are each independently a benzene, a naphthalene, a fluorene,a spiro-fluorene, an indene, a pyrrole, a thiophene, a furan, animidazole, a pyrazole, a thiazole, an isothiazole, an oxazole, anisoxazole, a pyridine, a pyrazine, a pyrimidine, a pyridazine, aquinoline, an isoquinoline, a benzoquinoline, a quinoxaline, aquinazoline, a carbazole, a benzoimidazole, a benzofuran, abenzothiophene, an isobenzothiophene, an benzoxazole, an isobenzoxazole,a triazole, a tetrazole, an oxadiazole, a triazine, a dibenzofuran, or adibenzothiophene, wherein CY₁ and CY₂ are optionally linked to eachother via a single bond or a first linking group; Y₁ to Y₄ are eachindependently C or N; Y₁ and Y₂ are linked to each other via a singlebond or a double bond, and Y₃ and Y₄ are linked to each other via asingle bond or a double bond; X₁ is N or CR₁; X₂ is N or CR₂; X₃ is N orCR₃; X₄ is N or CR₄; X₁₁ is N or CR₁₁; X₁₂ is N or CR₁₂; X₁₃ is N orCR₁₃; X₁₄ is N or CR₁₄; X₁₅ is N or CR₁₅; X₁₆ is N or CR₁₆; Z₁ to Z₄, R₁to R₄, R₁₁ to R₁₆, and Q₅₁ to Q₅₉ are each independently a hydrogen, adeuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitrogroup, an amino group, an amidino group, a hydrazine group, a hydrazonegroup, a carboxylic acid group or a salt thereof, a sulfonic acid groupor a salt thereof, a phosphoric acid group or a salt thereof, asubstituted or unsubstituted C₁-C₆₀ alkyl group, a substituted orunsubstituted C₂-C₆₀ alkenyl group, a substituted or unsubstitutedC₂-C₆₀ alkynyl group, a substituted or unsubstituted C₁-C₆₀ alkoxygroup, a substituted or unsubstituted C₃-C₁₀ cycloalkyl group, asubstituted or unsubstituted C₂-C₁₀ heterocycloalkyl group, asubstituted or unsubstituted C₃-C₁₀ cycloalkenyl group, a substituted orunsubstituted C₂-C₁₀ heterocycloalkenyl group, a substituted orunsubstituted C₆-C₆₀ aryl group, a substituted or unsubstituted C₆-C₆₀aryloxy group, a substituted or unsubstituted C₆-C₆₀ arylthio group, asubstituted or unsubstituted C₂-C₆₀ heteroaryl group, a substituted orunsubstituted monovalent non-aromatic condensed polycyclic group, asubstituted or unsubstituted monovalent non-aromatic condensedheteropolycyclic group, or —Si(Q₁)(Q₂)(Q₃); R₂₁ and R₂₂ are eachindependently a cyano group or a C₁-C₂₀ alkoxy group, a phenyl group, anaphthyl group, a phenanthrenyl group, an anthracenyl group, atriphenylenyl group, a pyrrolyl group, a thiophenyl group, a furanylgroup, an imidazolyl group, a pyrazolyl group, a pyridinyl group, apyrazinyl group, a pyrimidinyl group, a pyridazinyl group, an isoindolylgroup, a purinyl group, a quinolinyl group, an isoquinolinyl group, aquinoxalinyl group, a quinazolinyl group, a phenanthrolinyl group, abenzoimidazolyl group, a benzofuranyl group, a benzothiophenyl group, anisobenzothiazolyl group, a benzoxazolyl group, an isobenzoxazolyl group,a triazolyl group, a tetrazolyl group, an oxadiazolyl group, a triazinylgroup, a dibenzofuranyl group, or a dibenzothiophenyl group, a phenylgroup, a naphthyl group, a phenanthrenyl group, an anthracenyl group, atriphenylenyl group, a pyrrolyl group, a thiophenyl group, a furanylgroup, an imidazolyl group, a pyrazolyl group, a pyridinyl group, apyrazinyl group, a pyrimidinyl group, a pyridazinyl group, an isoindolylgroup, a purinyl group, a quinolinyl group, an isoquinolinyl group, aquinoxalinyl group, a quinazolinyl group, a phenanthrolinyl group, abenzoimidazolyl group, a benzofuranyl group, a benzothiophenyl group, anisobenzothiazolyl group, a benzoxazolyl group, an isobenzoxazolyl group,a triazolyl group, a tetrazolyl group, an oxadiazolyl group, a triazinylgroup, a dibenzofuranyl group, or a dibenzothiophenyl group, eachsubstituted with at least one of a deuterium, —F, —Cl, —Br, —I, ahydroxyl group, a cyano group, a nitro group, an amino group, an amidinogroup, a hydrazine group, a hydrazone group, a carboxylic acid group ora salt thereof, a sulfonic acid group or a salt thereof, a phosphoricacid group or a salt thereof, a C₂₀ alkyl group, a C₁-C₂₀ alkoxy group,a phenyl group, a naphthyl group, a phenanthrenyl group, an anthracenylgroup, a triphenylenyl group, a pyrrolyl group, a thiophenyl group, afuranyl group, an imidazolyl group, a pyrazolyl group, a pyridinylgroup, a pyrazinyl group, a pyrimidinyl group, a pyridazinyl group, anisoindolyl group, a purinyl group, a quinolinyl group, an isoquinolinylgroup, a quinoxalinyl group, a quinazolinyl group, a phenanthrolinylgroup, a benzoimidazolyl group, a benzofuranyl group, a benzothiophenylgroup, an isobenzothiazolyl group, a benzoxazolyl group, anisobenzoxazolyl group, a triazolyl group, a tetrazolyl group, anoxadiazolyl group, a triazinyl group, a dibenzofuranyl group, and adibenzothiophenyl group, or Si(Q₁)(Q₂)(Q₃), wherein Q₁ to Q₃ are eachindependently a hydrogen, a phenyl group, or a naphthyl group; and atleast one of R₂₁ and R₂₂ in Formula 5 is a cyano group or a C₁-C₂₀alkoxy group, a naphthyl group, a phenanthrenyl group, an anthracenylgroup, a triphenylenyl group, a pyrrolyl group, a thiophenyl group, afuranyl group, an imidazolyl group, a pyrazolyl group, a pyridinylgroup, a pyrazinyl group, a pyrimidinyl group, a pyridazinyl group, anisoindolyl group, a purinyl group, a quinolinyl group, an isoquinolinylgroup, a quinoxalinyl group, a quinazolinyl group, a phenanthrolinylgroup, a benzoimidazolyl group, a benzofuranyl group, a benzothiophenylgroup, an isobenzothiazolyl group, a benzoxazolyl group, anisobenzoxazolyl group, a triazolyl group, a tetrazolyl group, anoxadiazolyl group, a triazinyl group, a dibenzofuranyl group, or adibenzothiophenyl group, or a phenyl group, a naphthyl group, aphenanthrenyl group, an anthracenyl group, a triphenylenyl group, apyrrolyl group, a thiophenyl group, a furanyl group, an imidazolylgroup, a pyrazolyl group, a pyridinyl group, a pyrazinyl group, apyrimidinyl group, a pyridazinyl group, an isoindolyl group, a purinylgroup, a quinolinyl group, an isoquinolinyl group, a quinoxalinyl group,a quinazolinyl group, a phenanthrolinyl group, a benzoimidazolyl group,a benzofuranyl group, a benzothiophenyl group, an isobenzothiazolylgroup, a benzoxazolyl group, an isobenzoxazolyl group, a triazolylgroup, a tetrazolyl group, an oxadiazolyl group, a triazinyl group, adibenzofuranyl group, or a dibenzothiophenyl group, each substitutedwith at least one of a deuterium, —F, —Cl, —Br, —I, a hydroxyl group, acyano group, a nitro group, an amino group, an amidino group, ahydrazine group, a hydrazone group, a carboxylic acid group or a saltthereof, a sulfonic acid group or a salt thereof, a phosphoric acidgroup or a salt thereof, a C₁-C₂₀ alkoxy group, a phenyl group, anaphthyl group, a phenanthrenyl group, an anthracenyl group, atriphenylenyl group, a pyrrolyl group, a thiophenyl group, a furanylgroup, an imidazolyl group, a pyrazolyl group, a pyridinyl group, apyrazinyl group, a pyrimidinyl group, a pyridazinyl group, an isoindolylgroup, a purinyl group, a quinolinyl group, an isoquinolinyl group, aquinoxalinyl group, a quinazolinyl group, a phenanthrolinyl group, abenzoimidazolyl group, a benzofuranyl group, a benzothiophenyl group, anisobenzothiazolyl group, a benzoxazolyl group, an isobenzoxazolyl group,a triazolyl group, a tetrazolyl group, an oxadiazolyl group, a triazinylgroup, a dibenzofuranyl group, and a dibenzothiophenyl group; whereinR₂₁ and R₂₂ are optionally linked to each other via a single bond or asecond linking group represented by Formula 7, wherein when R₂₁ and R₂₂are not linked to each other, at least one of R₂₁ and R₂₂ is not asubstituted or unsubstituted phenyl group, a substituted orunsubstituted fluorenyl group, a substituted or unsubstituted naphthylgroup, a substituted or unsubstituted thiophenyl group, or a substitutedor unsubstituted pyridinyl group, and wherein when R₂₁ and R₂₂ arelinked to each other, L₂ represented by Formula 5 is represented byFormula 5A or 5B:*—(Z₃₂)_(b2)—*′;  Formula 7 wherein, in Formula 7, Z₃₂ is *—O—*′, *—S—*,*—N(Q₅₁)—*′, *—C(Q₅₂)(Q₅₃)—*′, *—C(Q₅₄)═C(Q₅₅)—*′, or

b2 is an integer selected from 1 to 10, and when b2 is 2 or greater,groups Z₃₂ are identical to or different from each other;

wherein, in Formulae 5A and 5B, Z₃ and Z₄ are the same as in Formula 5;Z₃₂ and b2 are the same as in Formula 7; X₃₁ is N or CR₃₁; X₃₂ is N orCR₃₂; X₃₃ is N or CR₃₃; X₃₄ is N or CR₃₄, X₃₅ is N or CR₃₅; X₃₆ is N orCR₃₆, X₃₇ is N or CR₃₇; X₃₈ is N or CR₃₈; provided that at least one ofX₃₁ to X₃₈ is N; and R₃₁ to R₃₈ are the same or different and each hasthe same definition as R₁; a1 and a2 are each independently an integerselected from 0 to 5; n1 and n2 are each independently 1 or 2; * and *′each indicates a binding site to M in Formula 1; when the ligand ofFormula 2 is represented by Formula 2A, a2 in Formula 2A is 2, and Z₂ inFormula 2A is —F; at least one of X₁₁ to X₁₆ in Formula 4 is N; thefollowing conditions regarding R₂₁ and R₂₂ in Formula 5 are excluded: i)where R₂₁ and R₂₂ are both ethyl groups, ii) where R₂₁ and R₂₂ are bothpropyl groups, iii) where R₂₁ and R₂₂ are both butyl groups, and iv)where R₂₁ and R₂₂ are both —Si(CH₃)₃; at least one substituent of thesubstituted C₁-C₆₀ alkyl group, the substituted C₂-C₆₀ alkenyl group,the substituted C₂-C₆₀ alkynyl group, the substituted C₁-C₆₀ alkoxygroup, the substituted C₃-C₁₀ cycloalkyl group, the substituted C₂-C₁₀heterocycloalkyl group, the substituted C₃-C₁₀ cycloalkenyl group, thesubstituted C₂-C₁₀ heterocycloalkenyl group, the substituted C₆-C₆₀ arylgroup, the substituted C₆-C₆₀ aryloxy group, the substituted C₆-C₆₀arylthio group, the substituted C₂-C₆₀ heteroaryl group, the substitutedmonovalent non-aromatic condensed polycyclic group, and the substitutedmonovalent non-aromatic condensed heteropolycyclic group is a deuterium,—F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, anamino group, an amidino group, a hydrazine group, a hydrazone group, acarboxylic acid group or a salt thereof, a sulfonic acid group or a saltthereof, a phosphoric acid group or a salt thereof, a C₁-C₆₀ alkylgroup, a C₂-C₆₀ alkenyl group, a C₂-C₆₀ alkynyl group, or a C₁-C₆₀alkoxy group, a C₁-C₆₀ alkyl group, a C₂-C₆₀ alkenyl group, a C₂-C₆₀alkynyl group, or a C₁-C₆₀ alkoxy group, each substituted with at leastone of a deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, anitro group, an amino group, an amidino group, a hydrazine group, ahydrazone group, a carboxylic acid group or a salt thereof, a sulfonicacid group or a salt thereof, a phosphoric acid group or a salt thereof,a C₃-C₁₀ cycloalkyl group, a C₂-C₁₀ heterocycloalkyl group, a C₃-C₁₀cycloalkenyl group, a C₂-C₁₀ heterocycloalkenyl group, a C₆-C₆₀ arylgroup, a C₆-C₆₀ aryloxy group, a C₆-C₆₀ arylthio group, a C₂-C₆₀heteroaryl group, a monovalent non-aromatic condensed polycyclic group,a monovalent non-aromatic condensed heteropolycyclic group,—N(Q₁₁)(Q₁₂), —Si(Q₁₃)(Q₁₄)(Q₁₅), and —B(Q₁₆)(Q₁₇), a C₃-C₁₀ cycloalkylgroup, a C₂-C₁₀ heterocycloalkyl group, a C₃-C₁₀ cycloalkenyl group, aC₂-C₁₀ heterocycloalkenyl group, a C₆-C₆₀ aryl group, a C₆-C₆₀ aryloxygroup, a C₆-C₆₀ arylthio group, a C₂-C₆₀ heteroaryl group, a monovalentnon-aromatic condensed polycyclic group, or a monovalent non-aromaticcondensed heteropolycyclic group, a C₃-C₁₀ cycloalkyl group, a C₂-C₁₀heterocycloalkyl group, a C₃-C₁₀ cycloalkenyl group, a C₂-C₁₀heterocycloalkenyl group, a C₆-C₆₀ aryl group, a C₆-C₆₀ aryloxy group, aC₆-C₆₀ arylthio group, a C₂-C₆₀ heteroaryl group, a monovalentnon-aromatic condensed polycyclic group, or a monovalent non-aromaticcondensed heteropolycyclic group, each substituted with at least one ofa deuterium, —F, —Cl, —Br, a hydroxyl group, a cyano group, a nitrogroup, an amino group, an amidino group, a hydrazine group, a hydrazonegroup, a carboxylic acid group or a salt thereof, a sulfonic acid groupor a salt thereof, a phosphoric acid group or a salt thereof, a C₁-C₆₀alkyl group, a C₂-C₆₀ alkenyl group, a C₂-C₆₀ alkynyl group, a C₁-C₆₀alkoxy group, a C₃-C₁₀ cycloalkyl group, a C₂-C₁₀ heterocycloalkylgroup, a C₃-C₁₀ cycloalkenyl group, a C₂-C₁₀ heterocycloalkenyl group, aC₆-C₆₀ aryl group, a C₆-C₆₀ aryloxy group, a C₆-C₆₀ arylthio group, aC₂-C₆₀ heteroaryl group, a monovalent non-aromatic condensed polycyclicgroup, a monovalent non-aromatic condensed heteropolycyclic group,—N(Q₂₁)(Q₂₂), —Si(Q₂₃)(Q₂₄)(Q₂₅), and —B(Q₂₆)(Q₂₇), or N(Q₃₁)(Q₃₂),—Si(Q₃₃)(Q₃₄)(Q₃₅), or —B(Q₃₆)(Q₃₇); wherein Q₁ to Q₃, Q₁₁ to Q₁₇, Q₂₁to Q₂₇, and Q₃₁ to Q₃₇ are each independently a hydrogen, a deuterium,—F, —Cl, —Br, a hydroxyl group, a cyano group, a nitro group, an aminogroup, an amidino group, a hydrazine group, a hydrazone group, acarboxylic acid group or a salt thereof, a sulfonic acid group or a saltthereof, a phosphoric acid group or a salt thereof, a C₁-C₆₀ alkylgroup, a C₂-C₆₀ alkenyl group, a C₂-C₆₀ alkynyl group, a C₁-C₆₀ alkoxygroup, a C₃-C₁₀ cycloalkyl group, a C₂-C₁₀ heterocycloalkyl group, aC₃-C₁₀ cycloalkenyl group, a C₂-C₁₀ heterocycloalkenyl group, a C₆-C₆₀aryl group, a C₆-C₆₀ aryloxy group, a C₆-C₆₀ arylthio group, a C₂-C₆₀heteroaryl group, a monovalent non-aromatic condensed polycyclic group,or a monovalent non-aromatic condensed heteropolycyclic group:


2. The organometallic compound of claim 1, wherein the organometalliccompound of Formula 1 is represented by Formula 1A, 1B, or 1C:

wherein, in Formulae 1A to 1C, M, CY₁, CY₂, Y₁ to Y₄, X₁ to X₄, X₁₁ toX₁₆, Z₁ to Z₄, R₂₁, R₂₂, n1, and n2 are the same as those defined inclaim
 1. 3. The organometallic compound of claim 1, wherein M is Ir orPt.
 4. The organometallic compound of claim 1, wherein CY₁ and CY₂ areeach independently a benzene, a naphthalene, a fluorene, a thiophene, afuran, an imidazole, a pyrazole, a pyridine, a pyrimidine, a quinoline,an isoquinoline, a benzoquinoline, a quinoxaline, a quinazoline, acarbazole, a benzoimidazole, a benzofuran, a benzothiophene, anisobenzothiophene, a triazole, a tetrazole, a triazine, a dibenzofuran,or a dibenzothiophene.
 5. The organometallic compound of claim 1,wherein CY₁ is a pyridine or an imidazole, and CY₂ is a benzene, apyridine, or a dibenzofuran.
 6. The organometallic compound of claim 1,wherein CY₁ and CY₂ are linked to each other via a single bond or thefirst linking group, and the first linking group is a linking grouprepresented by Formula 6:*—(Z₃₁)_(b1)—*′  Formula 6 wherein, in Formula 6, Z₃₁ is selected from*—O-′, *—N(Q₄₁)—*′, *—C(Q₄₂)(Q₄₃)—*′, *—C(Q₄₄)—C(Q₄₅)—*′, and

wherein Q₄₁ to Q₄₉ are each independently a hydrogen, a deuterium, —F,—Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, an aminogroup, an amidino group, a hydrazine group, a hydrazone group, acarboxylic acid group or a salt thereof, a sulfonic acid group or a saltthereof, a phosphoric acid group or a salt thereof, a C₁-C₂₀ alkylgroup, or a C₁-C₂₀ alkoxy group, a C₁-C₂₀ alkyl group or a C₁-C₂₀ alkoxygroup, each substituted with at least one of a deuterium, —F, —Cl, —Br,—I, a hydroxyl group, a cyano group, a nitro group, an amino group, anamidino group, a hydrazine group, a hydrazone group, a carboxylic acidgroup or a salt thereof, a sulfonic acid group or a salt thereof, aphosphoric acid group or a salt thereof, a phenyl group, a naphthylgroup, a pyridinyl group, and a pyrimidinyl group, or a phenyl group, anaphthyl group, a pyridinyl group, or a pyrimidinyl group.
 7. Theorganometallic compound of claim 1, wherein Li in Formula 1 is selectedfrom groups represented by Formulae 2-1 to 2-90:

wherein, in Formulae 2-1 to 2-90, Z₁ and Z₂ are the same as thosedefined in claim 1; Z_(1a) and Z_(1b) are the same or different and eachhas the same definition as Z₁; Z_(2a), Z_(2b) and Z_(2c) are the same ordifferent and each has the same definition as Z₂; a12 is 1 or 2; a13 isan integer selected from 1 to 3; a14 is an integer selected from 1 to 4;and * and *′ each indicates a binding site to M.
 8. The organometalliccompound of claim 1, wherein Li in Formula 1 is selected from groupsrepresented by Formulae 2-1A, 2-2a, 2-70A, and 2-87A:

wherein, in Formulae 2-1A, 2-2A, 2-70A, and 2-87A, Z₁ and Z₂ are thesame as those defined in claim 1, Z_(2a), Z_(2b), and Z_(2c) are thesame or different and each has the same definition as Z₂, and and *′each indicates a binding site to M.
 9. The organometallic compound ofclaim 1, wherein Z₁ to Z₄, R₁ to R₄, R₁₁ to R₁₆, R₂₁, R₂₂, and Q₅₁ toQ₅₉ are each independently a hydrogen, a deuterium, —F, —Cl, —Br, —I, ahydroxyl group, a cyano group, a nitro group, an amino group, an amidinogroup, a hydrazine group, a hydrazone group, a carboxylic acid group ora salt thereof, a sulfonic acid group or a salt thereof, a phosphoricacid group or a salt thereof, a C₁-C₂₀ alkyl group, or a C₁-C₂₀ alkoxygroup, a C₁-C₂₀ alkyl group or a C₁-C₂₀ alkoxy group, each substitutedwith at least one of a deuterium, —F, —Cl, —Br, —I, a hydroxyl group, acyano group, a nitro group, an amino group, an amidino group, ahydrazine group, a hydrazone group, a carboxylic acid group or a saltthereof, a sulfonic acid group or a salt thereof, a phosphoric acidgroup or a salt thereof, a phenyl group, a naphthyl group, a pyridinylgroup, and a pyrimidinyl group, a phenyl group, a pentalenyl group, anaphthyl group, an azulenyl group, a heptalenyl group, an indacenylgroup, an acenaphthyl group, a fluorenyl group, a spiro-fluorenyl group,a benzofluorenyl group, a dibenzofluorenyl group, a phenalenyl group, aphenanthrenyl group, an anthracenyl group, a fluoranthenyl group, atriphenylenyl group, a pyrenyl group, a chrysenyl group, a naphthacenylgroup, a picenyl group, a perylenyl group, a pentaphenyl group, ahexacenyl group, a pentacenyl group, a rubicenyl group, a coronenylgroup, a ovalenyl group, a pyrrolyl group, a thiophenyl group, a furanylgroup, an imidazolyl group, a pyrazolyl group, a thiazolyl group, anisothiazolyl group, a oxazolyl group, an isooxazolyl group, a pyridinylgroup, a pyrazinyl group, a pyrimidinyl group, a pyridazinyl group, anisoindolyl group, an indolyl group, an indazolyl group, a purinyl group,a quinolinyl group, an isoquinolinyl group, a benzoquinolinyl group, aphthalazinyl group, a naphthyridinyl group, a quinoxalinyl group, aquinazolinyl group, a cinnolinyl group, a carbazolyl group, aphenanthridinyl group, an acridinyl group, a phenanthrolinyl group, aphenazinyl group, a benzoimidazolyl group, a benzofuranyl group, abenzothiophenyl group, an isobenzothiazolyl group, a benzooxazolylgroup, an isobenzooxazolyl group, a triazolyl group, a tetrazolyl group,a oxadiazolyl group, a triazinyl group, a dibenzofuranyl group, adibenzothiophenyl group, a benzocarbazolyl group, a dibenzocarbazolylgroup, a thiadiazolyl group, an imidazopyridinyl group, or animidazopyrimidinyl group, a phenyl group, a pentalenyl group, a naphthylgroup, an azulenyl group, a heptalenyl group, an indacenyl group, anacenaphthyl group, a fluorenyl group, a spiro-fluorenyl group, abenzofluorenyl group, a dibenzofluorenyl group, a phenalenyl group, aphenanthrenyl group, an anthracenyl group, a fluoranthenyl group, atriphenylenyl group, a pyrenyl group, a chrysenyl group, a naphthacenylgroup, a picenyl group, a perylenyl group, a pentaphenyl group, ahexacenyl group, a pentacenyl group, a rubicenyl group, a coronenylgroup, an ovalenyl group, a pyrrolyl group, a thiophenyl group, afuranyl group, an imidazolyl group, a pyrazolyl group, a thiazolylgroup, an isothiazolyl group, an oxazolyl group, an isoxazolyl group, apyridinyl group, a pyrazinyl group, a pyrimidinyl group, a pyridazinylgroup, an isoindolyl group, an indolyl group, an indazolyl group, apurinyl group, a quinolinyl group, an isoquinolinyl group, abenzoquinolinyl group, a phthalazinyl group, a naphthyridinyl group, aquinoxalinyl group, a quinazolinyl group, a cinnolinyl group, acarbazolyl group, a phenanthridinyl group, an acridinyl group, aphenanthrolinyl group, a phenazinyl group, a benzoimidazolyl group, abenzofuranyl group, a benzothiophenyl group, an isobenzothiazolyl group,a benzoxazolyl group, an isobenzoxazolyl group, a triazolyl group, atetrazolyl group, an oxadiazolyl group, a triazinyl group, adibenzofuranyl group, a dibenzothiophenyl group, a benzocarbazolylgroup, a dibenzocarbazolyl group, an imidazopyridinyl group, or animidazopyrimidinyl group, each substituted with at least one of adeuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitrogroup, an amino group, an amidino group, a hydrazine group, a hydrazonegroup, a carboxylic acid group or a salt thereof, a sulfonic acid groupor a salt thereof, a phosphoric acid group or a salt thereof, a C₁-C₂₀alkyl group, a C₁-C₂₀ alkoxy group, a phenyl group, a pentalenyl group,an indenyl group, a naphthyl group, an azulenyl group, a heptalenylgroup, an indacenyl group, an acenaphthyl group, a fluorenyl group, aspiro-fluorenyl group, a benzofluorenyl group, a dibenzofluorenyl group,a phenalenyl group, a phenanthrenyl group, an anthracenyl group, afluoranthenyl group, a triphenylenyl group, a pyrenyl group, a chrysenylgroup, a naphthacenyl group, a picenyl group, a perylenyl group, apentaphenyl group, a hexacenyl group, a pentacenyl group, a rubicenylgroup, a coronenyl group, an ovalenyl group, a pyrrolyl group, athiophenyl group, a furanyl group, an imidazolyl group, a pyrazolylgroup, a thiazolyl group, an isothiazolyl group, an oxazolyl group, anisoxazolyl group, a pyridinyl group, a pyrazinyl group, a pyrimidinylgroup, a pyridazinyl group, an isoindolyl group, an indolyl group, anindazolyl group, a purinyl group, a quinolinyl group, an isoquinolinylgroup, a benzoquinolinyl group, a phthalazinyl group, a naphthyridinylgroup, a quinoxalinyl group, a quinazolinyl group, a cinnolinyl group, acarbazolyl group, a phenanthridinyl group, an acridinyl group, aphenanthrolinyl group, a phenazinyl group, a benzoimidazolyl group, abenzofuranyl group, a benzothiophenyl group, an isobenzothiazolyl group,a benzoxazolyl group, an isobenzoxazolyl group, a triazolyl group, atetrazolyl group, an oxadiazolyl group, a triazinyl group, adibenzofuranyl group, a dibenzothiophenyl group, a benzocarbazolylgroup, a dibenzocarbazolyl group, an imidazopyridinyl group, and animidazopyrimidinyl group, or Si(Q₁)(Q₂)(Q₃), wherein Q₁ to Q₃ are eachindependently a hydrogen, a deuterium, —F, —Cl, —Br, —I, a hydroxylgroup, a cyano group, a nitro group, an amino group, an amidino group, ahydrazine group, a hydrazone group, a carboxylic acid group or a saltthereof, a sulfonic acid group or a salt thereof, a phosphoric acidgroup or a salt thereof, a C₁-C₂₀ alkyl group, a C₁-C₂₀ alkoxy group, aphenyl group, a naphthyl group, an anthracenyl group, a pyrenyl group, aphenanthrenyl group, a fluorenyl group, a chrysenyl group, a carbazolylgroup, a benzocarbazolyl group, a dibenzocarbazolyl group, adibenzofuranyl group, a dibenzothiophenyl group, a pyridinyl group, apyrimidinyl group, a triazinyl group, a quinolinyl group, anisoquinolinyl group, a quinazolinyl group, or a quinoxalinyl group. 10.The organometallic compound of claim 1, wherein Z₁ to Z₄, R₁ to R₄, R₁₁to R₁₆, R₂₁, R₂₂, and Q₅₁ to Q₅₉ are each independently a hydrogen, adeuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitrogroup, an amino group, an amidino group, a hydrazine group, a hydrazonegroup, a carboxylic acid group or a salt thereof, a sulfonic acid groupor a salt thereof, a phosphoric acid group or a salt thereof, a C₁-C₂₀alkyl group, or a C₁-C₂₀ alkoxy group, a C₁-C₂₀ alkyl group or a C₁-C₂₀alkoxy group, each substituted with at least one of a deuterium, —F,—Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, an aminogroup, an amidino group, a hydrazine group, a hydrazone group, acarboxylic acid group or a salt thereof, a sulfonic acid group or a saltthereof, and a phosphoric acid group or a salt thereof, a phenyl group,a naphthyl group, a fluorenyl group, a phenanthrenyl group, ananthracenyl group, a fluoranthenyl group, a triphenylenyl group, apyrenyl group, a chrysenyl group, a pyrrolyl group, a thiophenyl group,a furanyl group, an imidazolyl group, a pyrazolyl group, a thiazolylgroup, an isothiazolyl group, an oxazolyl group, an isoxazolyl group, apyridinyl group, a pyrazinyl group, a pyrimidinyl group, a pyridazinylgroup, an isoindolyl group, an indolyl group, an indazolyl group, apurinyl group, a quinolinyl group, an isoquinolinyl group, abenzoquinolinyl group, a quinoxalinyl group, a quinazolinyl group, acinnolinyl group, a carbazolyl group, a phenanthrolinyl group, abenzoimidazolyl group, a benzofuranyl group, a benzothiophenyl group, anisobenzothiazolyl group, a benzoxazolyl group, an isobenzoxazolyl group,a triazolyl group, a tetrazolyl group, an oxadiazolyl group, a triazinylgroup, a dibenzofuranyl group, a dibenzothiophenyl group, abenzocarbazolyl group, a dibenzocarbazolyl group, an imidazopyridinylgroup, or an imidazopyrimidinyl group, a phenyl group, a naphthyl group,a fluorenyl group, a phenanthrenyl group, an anthracenyl group, afluoranthenyl group, a triphenylenyl group, a pyrenyl group, a chrysenylgroup, a pyrrolyl group, a thiophenyl group, a furanyl group, animidazolyl group, a pyrazolyl group, a thiazolyl group, an isothiazolylgroup, an oxazolyl group, an isoxazolyl group, a pyridinyl group, apyrazinyl group, a pyrimidinyl group, a pyridazinyl group, an isoindolylgroup, an indolyl group, an indazolyl group, a purinyl group, aquinolinyl group, an isoquinolinyl group, a benzoquinolinyl group, aquinoxalinyl group, a quinazolinyl group, a cinnolinyl group, acarbazolyl group, a phenanthrolinyl group, a benzoimidazolyl group, abenzofuranyl group, a benzothiophenyl group, an isobenzothiazolyl group,a benzoxazolyl group, an isobenzoxazolyl group, a triazolyl group, atetrazolyl group, an oxadiazolyl group, a triazinyl group, adibenzofuranyl group, a dibenzothiophenyl group, a benzocarbazolylgroup, a dibenzocarbazolyl group, an imidazopyridinyl group, or animidazopyrimidinyl group, each substituted with at least one of adeuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitrogroup, an amino group, an amidino group, a hydrazine group, a hydrazonegroup, a carboxylic acid group or a salt thereof, a sulfonic acid groupor a salt thereof, a phosphoric acid group or a salt thereof, a C₁-C₂₀alkyl group, a C₁-C₂₀ alkoxy group, a phenyl group, a naphthyl group, afluorenyl group, a phenanthrenyl group, an anthracenyl group, afluoranthenyl group, a triphenylenyl group, a pyrenyl group, a chrysenylgroup, a pyrrolyl group, a thiophenyl group, a furanyl group, animidazolyl group, a pyrazolyl group, a thiazolyl group, an isothiazolylgroup, an oxazolyl group, an isoxazolyl group, a pyridinyl group, apyrazinyl group, a pyrimidinyl group, a pyridazinyl group, an isoindolylgroup, an indolyl group, an indazolyl group, a purinyl group, aquinolinyl group, an isoquinolinyl group, a benzoquinolinyl group, aquinoxalinyl group, a quinazolinyl group, a cinnolinyl group, acarbazoyl group, a phenanthrolinyl group, a benzoimidazolyl group, abenzofuranyl group, a benzothiophenyl group, an isobenzothiazolyl group,a benzoxazolyl group, an isobenzoxazolyl group, a triazolyl group, atetrazolyl group, an oxadiazolyl group, a triazinyl group, adibenzofuranyl group, a dibenzothiophenyl group, a benzocarbazolylgroup, a dibenzocarbazolyl group, an imidazopyridinyl group, and animidazopyrimidinyl group, or —Si(Q₁)(Q₂)(Q₃), wherein Q₁ to Q₃ are eachindependently a hydrogen, a deuterium, —F, —Cl, —Br, —I, a hydroxylgroup, a cyano group, a nitro group, an amino group, an amidino group, ahydrazine group, a hydrazone group, a carboxylic acid group or a saltthereof, a sulfonic acid group or a salt thereof, a phosphoric acidgroup or a salt thereof, a C₁-C₂₀ alkyl group, a C₁-C₂₀ alkoxy group, aphenyl group, a naphthyl group, a pyridinyl group, a pyrimidinyl group,or a triazinyl group.
 11. The organometallic compound of claim 1,wherein Z₁ to Z₄, R₁ to R₄, R₁₁ to R₁₆, R₂₁, R₂₂, and Q₅₁ to Q₅₉ areeach independently a hydrogen, —F, a cyano group, a nitro group, amethyl group, an ethyl group, a n-propyl group, an isopropyl group, an-butyl group, an isobutyl group, a sec-butyl group, a tert-butyl group,a n-pentyl group, an isopentyl group, a sec-pentyl group, a tert-pentylgroup, a n-hexyl group, an isohexyl group, a sec-hexyl group, atert-hexyl group, a n-heptyl group, an isoheptyl group, a sec-heptylgroup, a tert-heptyl group, a n-octyl group, an isooctyl group, asec-octyl group, a tert-octyl group, a n-nonyl group, an isononyl group,a sec-nonyl group, a tert-nonyl group, a n-decyl group, an isodecylgroup, a sec-decyl group, a tert-decyl group, a methoxy group, an ethoxygroup, a propoxy group, a butoxy group, a pentoxy group, a phenyl group,or a naphthyl group, a methyl group, an ethyl group, a n-propyl group,an isopropyl group, a n-butyl group, an isobutyl group, a sec-butylgroup, a tert-butyl group, a n-pentyl group, an isopentyl group, asec-pentyl group, a tert-pentyl group, a n-hexyl group, an isohexylgroup, a sec-hexyl group, a tert-hexyl group, a n-heptyl group, anisoheptyl group, a sec-heptyl group, a tert-heptyl group, a n-octylgroup, a isooctyl group, a sec-octyl group, a tert-octyl group, an-nonyl group, an isononyl group, a sec-nonyl group, a tert-nonyl group,a n-decyl group, an isodecyl group, a sec-decyl group, a tert-decylgroup, a methoxy group, an ethoxy group, a propoxy group, a butoxygroup, a pentoxy group, a phenyl group, or a naphthyl group, eachsubstituted with at least one of —F, a cyano group, and a nitro group,or Si(Q₁)(Q₂)(Q₃), wherein Q₁ to Q₃ are each independently a hydrogen, aC₁-C₂₀ alkoxy group, a phenyl group, a naphthyl group, a pyridinylgroup, a pyrimidinyl group, or a triazinyl group.
 12. The organometalliccompound of claim 1, wherein at least one of X₁ to X₄ in Formula 3 is N.13. The organometallic compound of claim 1, wherein L₂ in Formula 1 isrepresented by one of Formulae 3-1 to 3-4 and Formulae 4-1 to 4-4:

wherein, in Formulae 3-1 to 3-4, and Formulae 4-1 to 4-4, Z₃, Z₄, R₁ toR₄, and R₁₁ to R₁₆ are each independently a hydrogen, a deuterium, —F,—Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, an aminogroup, an amidino group, a hydrazine group, a hydrazone group, acarboxylic acid group or a salt thereof, a sulfonic acid group or a saltthereof, a phosphoric acid group or a salt thereof, a C₁-C₂₀ alkylgroup, or a C₁-C₂₀ alkoxy group, a C₁-C₂₀ alkyl group or a C₁-C₂₀ alkoxygroup, each substituted with at least one of a deuterium, —F, —Cl, —Br,—I, a hydroxyl group, a cyano group, a nitro group, an amino group, anamidino group, a hydrazine group, a hydrazone group, a carboxylic acidgroup or a salt thereof, a sulfonic acid group or a salt thereof, and aphosphoric acid group or a salt thereof, a phenyl group, a naphthylgroup, a fluorenyl group, a phenanthrenyl group, an anthracenyl group, afluoranthenyl group, a triphenylenyl group, a pyrenyl group, a chrysenylgroup, a pyrrolyl group, a thiophenyl group, a furanyl group, animidazolyl group, a pyrazolyl group, a thiazolyl group, an isothiazolylgroup, an oxazolyl group, an isoxazolyl group, a pyridinyl group, apyrazinyl group, a pyrimidinyl group, a pyridazinyl group, an isoindolylgroup, an indolyl group, an indazolyl group, a purinyl group, aquinolinyl group, an isoquinolinyl group, a benzoquinolinyl group, aquinoxalinyl group, a quinazolinyl group, a cinnolinyl group, acarbazolyl group, a phenanthrolinyl group, a benzoimidazolyl group, abenzofuranyl group, a benzothiophenyl group, an isobenzothiazolyl group,a benzoxazolyl group, an isobenzoxazolyl group, a triazolyl group, atetrazolyl group, an oxadiazolyl group, a triazinyl group, adibenzo(uranyl group, a dibenzothiophenyl group, a benzocarbazolylgroup, a dibenzocarbazolyl group, an imidazopyridinyl group, or animidazopyrimidinyl group, or a phenyl group, a naphthyl group, afluorenyl group, a phenanthrenyl group, an anthracenyl group, afluoranthenyl group, a triphenylenyl group, a pyrenyl group, a chrysenylgroup, a pyrrolyl group, a thiophenyl group, a furanyl group, animidazolyl group, a pyrazolyl group, a thiazolyl group, an isothiazolylgroup, an oxazolyl group, an isoxazolyl group, a pyridinyl group, apyrazinyl group, a pyrimidinyl group, a pyridazinyl group, an isoindolylgroup, an indolyl group, an indazolyl group, a purinyl group, aquinolinyl group, an isoquinolinyl group, a benzoquinolinyl group, aquinoxalinyl group, a quinazolinyl group, a cinnolinyl group, acarbazolyl group, a phenanthrolinyl group, a benzoimidazolyl group, abenzofuranyl group, a benzothiophenyl group, an isobenzothiazolyl group,a benzoxazolyl group, an isobenzoxazolyl group, a triazolyl group, atetrazolyl group, an oxadiazolyl group, a triazinyl group, adibenzofuranyl group, a dibenzothiophenyl group, a benzocarbazolylgroup, a dibenzocarbazolyl group, an imidazopyridinyl group, or animidazopyrimidinyl group, each substituted with at least one of adeuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitrogroup, an amino group, an amidino group, a hydrazine group, a hydrazonegroup, a carboxylic acid group or a salt thereof, a sulfonic acid groupor a salt thereof, a phosphoric acid group or a salt thereof, a C₁-C₂₀alkyl group, a C₁-C₂₀ alkoxy group, a phenyl group, a naphthyl group, afluorenyl group, a phenanthrenyl group, an anthracenyl group, afluoranthenyl group, a triphenylenyl group, a pyrenyl group, a chrysenylgroup, a pyrrolyl group, a thiophenyl group, a furanyl group, animidazolyl group, a pyrazolyl group, a thiazolyl group, an isothiazolylgroup, an oxazolyl group, an isoxazolyl group, a pyridinyl group, apyrazinyl group, a pyrimidinyl group, a pyridazinyl group, an isoindolylgroup, an indolyl group, an indazolyl group, a purinyl group, aquinolinyl group, an isoquinolinyl group, a benzoquinolinyl group, aquinoxalinyl group, a quinazolinyl group, a cinnolinyl group, acarbazolyl group, a phenanthrolinyl group, a benzoimidazolyl group, abenzofuranyl group, a benzothiophenyl group, an isobenzothiazolyl group,a benzoxazolyl group, an isobenzoxazolyl group, a triazolyl group, atetrazolyl group, an oxadiazolyl group, a triazinyl group, adibenzofuranyl group, a dibenzothiophenyl group, a benzocarbazolylgroup, a dibenzocarbazolyl group, an imidazopyridinyl group, and animidazopyrimidinyl group; and * and *′ each indicates a binding site toM.
 14. The organometallic compound of claim 1, wherein R₃₁ to R₃₈ inFormulae 5A and 5B are each independently a hydrogen, —F, a cyano group,a nitro group, a methyl group, an ethyl group, a n-propyl group, anisopropyl group, a n-butyl group, an isobutyl group, a sec-butyl group,a tert-butyl group, a n-pentyl group, an isopentyl group, a sec-pentylgroup, a tert-pentyl group, a n-hexyl group, an isohexyl group, asec-hexyl group, a tert-hexyl group, a n-heptyl group, an isoheptylgroup, a sec-heptyl group, a tert-heptyl group, a n-octyl group, anisooctyl group, a sec-octyl group, a tert-octyl group, a n-nonyl group,an isononyl group, a sec-nonyl group, a tert-nonyl group, a n-decylgroup, an isodecyl group, a sec-decyl group, a tert-decyl group, amethoxy group, an ethoxy group, a propoxy group, a butoxy group, apentoxy group, a phenyl group, or a naphthyl group, or a methyl group,an ethyl group, a n-propyl group, an isopropyl group, a n-butyl group,an isobutyl group, a sec-butyl group, a tert-butyl group, a n-pentylgroup, an isopentyl group, a sec-pentyl group, a tert-pentyl group, an-hexyl group, an isohexyl group, a sec-hexyl group, a tert-hexyl group,a n-heptyl group, an isoheptyl group, a sec-heptyl group, a tert-heptylgroup, a n-octyl group, an isooctyl group, a sec-octyl group, atert-octyl group, a n-nonyl group, an isononyl group, a sec-nonyl group,a tert-nonyl group, a n-decyl group, an isodecyl group, a sec-decylgroup, a tert-decyl group, a methoxy group, an ethoxy group, a propoxygroup, a butoxy group, a pentoxy group, a phenyl group, or a naphthylgroup, each substituted with at least one of —F, a cyano group, and anitro group.
 15. An organic light-emitting device comprising: a firstelectrode; a second electrode; and an organic layer disposed between thefirst electrode and the second electrode, wherein the organic layercomprises an emission layer and at least one of the organometalliccompounds of claim
 1. 16. The organic light-emitting device of claim 15,wherein the first electrode is an anode, the second electrode is acathode, and the organic layer comprises i) a hole transport regiondisposed between the first electrode and the emission layer andcomprising at least one of a hole injection layer, a hole transportlayer, and an electron blocking layer, and ii) an electron transportregion disposed between the emission layer and the second electrode andcomprising at least one of a hole blocking layer, an electron transportlayer, and an electron injection layer.
 17. The organic light-emittingdevice of claim 15, wherein the emission layer comprises the at leastone of the organometallic compounds.
 18. The organic light-emittingdevice of claim 17, wherein the emission layer further comprises a host.19. An organometallic compound represented by Formula 1:M(L₁)_(n1)(L₂)_(n2)  Formula 1 wherein, in Formula 1, M is Ir, Pt, Os,Ti, Zr, Hf, Eu, Tb, or Tm; n1 and n2 are each independently 1 or 2; L₁is a ligand represented by Formula 2,

wherein, in Formula 2, CY₁ and CY₂ are each independently a benzene, anaphthalene, a fluorene, a spiro-fluorene, an indene, a pyrrole, athiophene, a furan, an imidazole, a pyrazole, a thiazole, anisothiazole, an oxazole, an isoxazole, a pyridine, a pyrazine, apyrimidine, a pyridazine, a quinoline, an isoquinoline, abenzoquinoline, a quinoxaline, a quinazoline, a carbazole, abenzoimidazole, a benzofuran, a benzothiophene, an isobenzothiophene, anbenzoxazole, an isobenzoxazole, a triazole, a tetrazole, an oxadiazole,a triazine, a dibenzofuran, or a dibenzothiophene, wherein CY₁ and CY₂are optionally linked to each other via a single bond or a first linkinggroup; Y₁ to Y₄ are each independently C or N; Y₁ and Y₂ are linked toeach other via a single bond or a double bond, and Y₃ and Y₄ are linkedto each other via a single bond or a double bond; Z₁ and Z₂ are eachindependently a hydrogen, a deuterium, —F, —Cl, —Br, —I, a hydroxylgroup, a cyano group, a nitro group, an amino group, an amidino group, ahydrazine group, a hydrazone group, a carboxylic acid group or a saltthereof, a sulfonic acid group or a salt thereof, a phosphoric acidgroup or a salt thereof, a substituted or unsubstituted C₁-C₆₀ alkylgroup, a substituted or unsubstituted C₂-C₆₀ alkenyl group, asubstituted or unsubstituted C₂-C₆₀ alkynyl group, a substituted orunsubstituted C₁-C₆₀ alkoxy group, a substituted or unsubstituted C₃-C₁₀cycloalkyl group, a substituted or unsubstituted C₂-C₁₀ heterocycloalkylgroup, a substituted or unsubstituted C₃-C₁₀ cycloalkenyl group, asubstituted or unsubstituted C₂-C₁₀ heterocycloalkenyl group, asubstituted or unsubstituted C₆-C₆₀ aryl group, a substituted orunsubstituted C₆-C₆₀ aryloxy group, a substituted or unsubstitutedC₆-C₆₀ arylthio group, a substituted or unsubstituted C₂-C₆₀ heteroarylgroup, a substituted or unsubstituted monovalent non-aromatic condensedpolycyclic group, a substituted or unsubstituted monovalent non-aromaticcondensed heteropolycyclic group, or —Si(Q₁)(Q₂)(Q₃); at least onesubstituent of the substituted C₁-C₆₀ alkyl group, the substitutedC₂-C₆₀ alkenyl group, the substituted C₂-C₆₀ alkynyl group, thesubstituted C₁-C₆₀ alkoxy group, the substituted C₃-C₁₀ cycloalkylgroup, the substituted C₂-C₁₀ heterocycloalkyl group, the substitutedC₃-C₁₀ cycloalkenyl group, the substituted C₂-C₁₀ heterocycloalkenylgroup, the substituted C₆-C₆₀ aryl group, the substituted C₆-C₆₀ aryloxygroup, the substituted C₆-C₆₀ arylthio group, the substituted C₂-C₆₀heteroaryl group, the substituted monovalent non-aromatic condensedpolycyclic group, and the substituted monovalent non-aromatic condensedheteropolycyclic group is a deuterium, —F, —Cl, —Br, —I, a hydroxylgroup, a cyano group, a nitro group, an amino group, an amidino group, ahydrazine group, a hydrazone group, a carboxylic acid group or a saltthereof, a sulfonic acid group or a salt thereof, a phosphoric acidgroup or a salt thereof, a C₁-C₆₀ alkyl group, a C₂-C₆₀ alkenyl group, aC₂-C₆₀ alkynyl group, or a C₁-C₆₀ alkoxy group, a C₁-C₆₀ alkyl group, aC₂-C₆₀ alkenyl group, a C₂-C₆₀ alkynyl group, or a C₁-C₆₀ alkoxy group,each substituted with at least one of a deuterium, —F, —Cl, —Br, —I, ahydroxyl group, a cyano group, a nitro group, an amino group, an amidinogroup, a hydrazine group, a hydrazone group, a carboxylic acid group ora salt thereof, a sulfonic acid group or a salt thereof, a phosphoricacid group or a salt thereof, a C₃-C₁₀ cycloalkyl group, a C₂-C₁₀heterocycloalkyl group, a C₃-C₁₀ cycloalkenyl group, a C₂-C₁₀heterocycloalkenyl group, a C₆-C₆₀ aryl group, a C₆-C₆₀ aryloxy group, aC₆-C₆₀ arylthio group, a C₂-C₆₀ heteroaryl group, a monovalentnon-aromatic condensed polycyclic group, a monovalent non-aromaticcondensed heteropolycyclic group, —N(Q₁₁)(Q₁₂), —Si(Q₁₃)(Q₁₄)(Q₁₅), and—B(Q₁₆)(Q₁₇), a C₃-C₁₀ cycloalkyl group, a C₂-C₁₀ heterocycloalkylgroup, a C₃-C₁₀ cycloalkenyl group, a C₂-C₁₀ heterocycloalkenyl group, aC₆-C₆₀ aryl group, a C₆-C₆₀ aryloxy group, a C₆-C₆₀ arylthio group, aC₂-C₆₀ heteroaryl group, a monovalent non-aromatic condensed polycyclicgroup, or a monovalent non-aromatic condensed heteropolycyclic group, aC₃-C₁₀ cycloalkyl group, a C₂-C₁₀ heterocycloalkyl group, a C₃-C₁₀cycloalkenyl group, a C₂-C₁₀ heterocycloalkenyl group, a C₆-C₆₀ arylgroup, a C₆-C₆₀ aryloxy group, a C₆-C₆₀ arylthio group, a C₂-C₆₀heteroaryl group, a monovalent non-aromatic condensed polycyclic group,or a monovalent non-aromatic condensed heteropolycyclic group, eachsubstituted with at least one of a deuterium, —F, —Cl, —Br, —I, ahydroxyl group, a cyano group, a nitro group, an amino group, an amidinogroup, a hydrazine group, a hydrazone group, a carboxylic acid group ora salt thereof, a sulfonic acid group or a salt thereof, a phosphoricacid group or a salt thereof, a C₁-C₆₀ alkyl group, a C₂-C₆₀ alkenylgroup, a C₂-C₆₀ alkynyl group, a C₁-C₆₀ alkoxy group, a C₃-C₁₀cycloalkyl group, a C₂-C₁₀ heterocycloalkyl group, a C₃-C₁₀ cycloalkenylgroup, a C₂-C₁₀ heterocycloalkenyl group, a C₆-C₆₀ aryl group, a C₆-C₆₀aryloxy group, a C₆-C₆₀ arylthio group, a C₂-C₆₀ heteroaryl group, amonovalent non-aromatic condensed polycyclic group, a monovalentnon-aromatic condensed heteropolycyclic group, —N(Q₂₁)(Q₂₂),—Si(Q₂₃)(Q₂₄)(Q₂₅), and —B(Q₂₆)(Q₂₇), or —N(Q₃₁)(Q₃₂),—Si(Q₃₃)(Q₃₄)(Q₃₅), or —B(Q₃₆)(Q₃₇); wherein Q₁ to Q₃, Q₁₁ to Q₁₇, Q₂₁to Q₂₇, and Q₃₁ to Q₃₇ are each independently a hydrogen, a deuterium,—F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, anamino group, an amidino group, a hydrazine group, a hydrazone group, acarboxylic acid group or a salt thereof, a sulfonic acid group or a saltthereof, a phosphoric acid group or a salt thereof, a C₁-C₆₀ alkylgroup, a C₂-C₆₀ alkenyl group, a C₂-C₆₀ alkynyl group, a C₁-C₆₀ alkoxygroup, a C₃-C₁₀ cycloalkyl group, a C₂-C₁₀ heterocycloalkyl group, aC₃-C₁₀ cycloalkenyl group, a C₂-C₁₀ heterocycloalkenyl group, a C₆-C₆₀aryl group, a C₆-C₆₀ aryloxy group, a C₆-C₆₀ arylthio group, a C₂-C₆₀heteroaryl group, a monovalent non-aromatic condensed polycyclic group,or a monovalent non-aromatic condensed heteropolycyclic group; a1 and a2are each independently an integer selected from 0 to 5; * and *′ eachindicates a binding site to M in Formula 1; L₂ in Formula 1 is selectedfrom groups represented by Formulae 5-2, 5-8 to 5-12, and 5-17 to 5-25:

wherein, in Formulae 5-2, 5-8 to 5-12, and 5-17 to 5-25, Z₃, Z₄, R₃₁ toR₃₈, and Q₅₂ to Q₅₅ are each independently a hydrogen, a deuterium, —F,—Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, an aminogroup, an amidino group, a hydrazine group, a hydrazone group, acarboxylic acid group or a salt thereof, a sulfonic acid group or a saltthereof, a phosphoric acid group or a salt thereof, a C₁-C₂₀ alkylgroup, or a C₁-C₂₀ alkoxy group, a C₁-C₂₀ alkyl group or a C₁-C₂₀ alkoxygroup, each substituted with at least one of a deuterium, —F, —Cl, —Br,—I, a hydroxyl group, a cyano group, a nitro group, an amino group, anamidino group, a hydrazine group, a hydrazone group, a carboxylic acidgroup or a salt thereof, a sulfonic acid group or a salt thereof, and aphosphoric acid group or a salt thereof, a phenyl group, a naphthylgroup, a fluorenyl group, a phenanthrenyl group, an anthracenyl group, afluoranthenyl group, a triphenylenyl group, a pyrenyl group, a chrysenylgroup, a pyrrolyl group, a thiophenyl group, a furanyl group, animidazolyl group, a pyrazolyl group, a thiazolyl group, an isothiazolylgroup, an oxazolyl group, an isoxazolyl group, a pyridinyl group, apyrazinyl group, a pyrimidinyl group, a pyridazinyl group, an isoindolylgroup, an indolyl group, an indazolyl group, a purinyl group, aquinolinyl group, an isoquinolinyl group, a benzoquinolinyl group, aquinoxalinyl group, a quinazolinyl group, a cinnolinyl group, acarbazolyl group, a phenanthrolinyl group, a benzoimidazolyl group, abenzofuranyl group, a benzothiophenyl group, an isobenzothiazolyl group,a benzoxazolyl group, an isobenzoxazolyl group, a triazolyl group, atetrazolyl group, an oxadiazolyl group, a triazinyl group, adibenzofuranyl group, a dibenzothiophenyl group, a benzocarbazolylgroup, a dibenzocarbazolyl group, an imidazopyridinyl group, or animidazopyrimidinyl group, or a phenyl group, a naphthyl group, afluorenyl group, a phenanthrenyl group, an anthracenyl group, afluoranthenyl group, a triphenylenyl group, a pyrenyl group, a chrysenylgroup, a pyrrolyl group, a thiophenyl group, a furanyl group, animidazolyl group, a pyrazolyl group, a thiazolyl group, an isothiazolylgroup, an oxazolyl group, an isoxazolyl group, a pyridinyl group, apyrazinyl group, a pyrimidinyl group, a pyridazinyl group, an isoindolylgroup, an indolyl group, an indazolyl group, a purinyl group, aquinolinyl group, an isoquinolinyl group, a benzoquinolinyl group, aquinoxalinyl group, a quinazolinyl group, a cinnolinyl group, acarbazolyl group, a phenanthrolinyl group, a benzoimidazolyl group, abenzofuranyl group, a benzothiophenyl group, an isobenzothiazolyl group,a benzoxazolyl group, an isobenzoxazolyl group, a triazolyl group, atetrazolyl group, an oxadiazolyl group, a triazinyl group, adibenzofuranyl group, a dibenzothiophenyl group, a benzocarbazolylgroup, a dibenzocarbazolyl group, an imidazopyridinyl group, or animidazopyrimidinyl group, each substituted with at least one of adeuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitrogroup, an amino group, an amidino group, a hydrazine group, a hydrazonegroup, a carboxylic acid group or a salt thereof, a sulfonic acid groupor a salt thereof, a phosphoric acid group or a salt thereof, a C₁-C₂₀alkyl group, a C₁-C₂₀ alkoxy group, a phenyl group, a naphthyl group, afluorenyl group, a phenanthrenyl group, an anthracenyl group, afluoranthenyl group, a triphenylenyl group, a pyrenyl group, a chrysenylgroup, a pyrrolyl group, a thiophenyl group, a furanyl group, animidazolyl group, a pyrazolyl group, a thiazolyl group, an isothiazolylgroup, an oxazolyl group, an isoxazolyl group, a pyridinyl group, apyrazinyl group, a pyrimidinyl group, a pyridazinyl group, an isoindolylgroup, an indolyl group, an indazolyl group, a purinyl group, aquinolinyl group, an isoquinolinyl group, a benzoquinolinyl group, aquinoxalinyl group, a quinazolinyl group, a cinnolinyl group, acarbazolyl group, a phenanthrolinyl group, a benzoimidazolyl group, abenzofuranyl group, a benzothiophenyl group, an isobenzothiazolyl group,a benzoxazolyl group, an isobenzoxazolyl group, a triazolyl group, atetrazolyl group, an oxadiazolyl group, a triazinyl group, adibenzofuranyl group, a dibenzothiophenyl group, a benzocarbazolylgroup, a dibenzocarbazolyl group, an imidazopyridinyl group, and animidazopyrimidinyl group; d1 is an integer selected from 1 to 4; d2 isan integer selected from 1 to 5; d3 is an integer selected from 1 to 3;d4 is 1 or 2; and d5 is an integer selected from 1 to
 7. 20. Anorganometallic compound represented by Formula 1:M(L₁)_(n1)(L₂)_(n2)  Formula 1 wherein, in Formula 1, M is Ir, Pt, Os,Ti, Zr, Hf, Eu, Tb, or Tm; n1 and n2 are each independently 1 or 2; L₁is a ligand represented by Formula 2,

wherein, in Formula 2, CY₁ is a pyridine or an imidazole; CY₂ is abenzene, a pyridine, or a dibenzofuran; Y₁ to Y₄ are each independentlyC or N; Y₁ and Y₂ are linked to each other via a single bond or a doublebond, and Y₃ and Y₄ are linked to each other via a single bond or adouble bond; Z₁ and Z₂ are each independently a hydrogen, —F, a cyanogroup, a nitro group, a methyl group, an ethyl group, a n-propyl group,an isopropyl group, a n-butyl group, an isobutyl group, a sec-butylgroup, a tert-butyl group, a n-pentyl group, an isopentyl group, asec-pentyl group, a tert-pentyl group, a n-hexyl group, an isohexylgroup, a sec-hexyl group, a tert-hexyl group, a n-heptyl group, anisoheptyl group, a sec-heptyl group, a tert-heptyl group, a n-octylgroup, an isooctyl group, a sec-octyl group, a tert-octyl group, an-nonyl group, an isononyl group, a sec-nonyl group, a tert-nonyl group,a n-decyl group, an isodecyl group, a sec-decyl group, a tert-decylgroup, a methoxy group, an ethoxy group, a propoxy group, a butoxygroup, a pentoxy group, a phenyl group, or a naphthyl group, or a methylgroup, an ethyl group, a n-propyl group, an isopropyl group, a n-butylgroup, an isobutyl group, a sec-butyl group, a tert-butyl group, an-pentyl group, an isopentyl group, a sec-pentyl group, a tert-pentylgroup, a n-hexyl group, an isohexyl group, a sec-hexyl group, atert-hexyl group, a n-heptyl group, an isoheptyl group, a sec-heptylgroup, a tert-heptyl group, a n-octyl group, an isooctyl group, asec-octyl group, a tert-octyl group, a n-nonyl group, an isononyl group,a sec-nonyl group, a tert-nonyl group, a n-decyl group, an isodecylgroup, a sec-decyl group, a tert-decyl group, a methoxy group, an ethoxygroup, a propoxy group, a butoxy group, a pentoxy group, a phenyl group,or a naphthyl group, each substituted with at least one of —F, a cyanogroup, and a nitro group; and L₂ in Formula 1 is represented by one ofFormulae 3-1 to 3-4, Formulae 4-1 to 4-4, and Formulae 5-2, 5-8 to 5-12,and 5-17 to 5-25:

wherein, in Formulae 3-1 to 3-4, Formulae 4-1 to 4-4, and Formulae 5-2,5-8 to 5-12, and 5-17 to 5-25, Z₃, Z₄, R₁ to R₄, R₁₁ to R₁₆, R₃₁ to R₃₈,and Q₅₂ to Q₅₅ are each independently a hydrogen, —F, a cyano group, anitro group, a methyl group, an ethyl group, a n-propyl group, anisopropyl group, a n-butyl group, an isobutyl group, a sec-butyl group,a tert-butyl group, a n-pentyl group, an isopentyl group, a sec-pentylgroup, a tert-pentyl group, a n-hexyl group, an isohexyl group, asec-hexyl group, a tert-hexyl group, a n-heptyl group, an isoheptylgroup, a sec-heptyl group, a tert-heptyl group, a n-octyl group, anisooctyl group, a sec-octyl group, a tert-octyl group, a n-nonyl group,an isononyl group, a sec-nonyl group, a tert-nonyl group, a n-decylgroup, an isodecyl group, a sec-decyl group, a tert-decyl group, amethoxy group, an ethoxy group, a propoxy group, a butoxy group, apentoxy group, a phenyl group, or a naphthyl group, or a methyl group,an ethyl group, a n-propyl group, an isopropyl group, a n-butyl group,an isobutyl group, a sec-butyl group, a tert-butyl group, a n-pentylgroup, an isopentyl group, a sec-pentyl group, a tert-pentyl group, an-hexyl group, an isohexyl group, a sec-hexyl group, a tert-hexyl group,a n-heptyl group, an isoheptyl group, a sec-heptyl group, a tert-heptylgroup, a n-octyl group, an isooctyl group, a sec-octyl group, atert-octyl group, a n-nonyl group, an isononyl group, a sec-nonyl group,a tert-nonyl group, a n-decyl group, an isodecyl group, a sec-decylgroup, a tert-decyl group, a methoxy group, an ethoxy group, a propoxygroup, a butoxy group, a pentoxy group, a phenyl group, or a naphthylgroup, each substituted with at least one of —F, a cyano group, and anitro group; d1 is an integer selected from 1 to 4; d2 is an integerselected from 1 to 5; d3 is an integer selected from 1 to 3; d4 is 1 or2; d5 is an integer selected from 1 to 7; and * and *′ each indicates abinding site to M in Formula
 1. 21. An organometallic compound, whereinthe organometallic compound is one of Compounds 1 to 22, 24 to 33,35-40, 42-43, and 45-56: